He relates the parable to them, saying, Truly, truly, I say to you . It concerns two things, a thief and the shepherd of the sheep. Thus he does three things. First, he mentions the mark of a thief and robber; secondly, a characteristic of the shepherd (v 2); thirdly, the effect each of these has (v 4).
1365 To understand this parable we must consider who the sheep are, namely, that they are the faithful of Christ and those in the grace of God: "We are the people of his pasture, and the sheep of his hand" (Ps 95:7); "You, the people, are the sheep of my pasture" [Ez 34:31]. And so the sheepfold is the multitude of the faithful: "I will surely gather all of you, O Jacob, I will gather the remnant of Israel; I will set them together like sheep in a fold" (Mic 2:12). The door of the sheepfold is explained in different ways by Chrysostom and by Augustine.
1366 According to Chrysostom, Christ calls Sacred Scripture the door, according to "Pray for us also that God may open to us a door for the word" (Col 4:3). Sacred Scripture is called a door, as Chrysostom says, first of all, because through it we have access to the knowledge of God: "which he promised beforehand through his prophets in the holy scriptures" (Rom 1:2). Secondly, for just as the door guards the sheep, so Sacred Scripture preserves the life of the faithful: "You search the scriptures, because you think that in them you have eternal life" (5:39). Thirdly, because the door keeps the wolf from entering; so Sacred Scripture keeps heretics from harming the faithful: "Every scripture inspired by God is also profitable for teaching, for reproof, for correction" (2 Tim 3:16). So, the one who does not enter by the door is the one who does not enter by Sacred Scripture to teach the people. Our Lord says of such: "In vain do they worship me, teaching as doctrines the precepts of men" (Matt 15:9); "You have made void the word of God" (Matt 15:6). This, then, is the mark of the thief: he does not enter by the door, but in some other way. [1]
He adds that the thief climbs , and this is appropriate to this parable because thieves climb the walls, instead of entering by the door, and drop into the sheepfold. It also corresponds to the truth, because the reason why some teach what conflicts with Sacred Scripture is due to pride: "If any one teaches otherwise and does not agree with the sound words of our Lord Jesus Christ and the teaching which accords with godliness, he is puffed up with conceit, he knows nothing" (1 Tim 6:3). Referring to this he says that such a person climbs , that is, through pride. The one who climbs in by another way, that man is a thief , because he snatches what is not his, and a robber , because he kills what he snatches: "If thieves came to you, if plunderers by night - how you have been destroyed" (Obad v 5).
According to this explanation, the relation with what preceded is made in this way: Since our Lord had said, "If you were blind, you would have no guilt," the Jews might have answered: "We do not believe you, but this is not due to our blindness. It is because of your own error that we have turned away from you." And so our Lord rejects this, and wishes to show that he is not in error because he enters by the door, by Sacred Scripture, that is, he teaches what is contained in Sacred Scripture.
1367 Against this interpretation is the fact that when our Lord explains this further on, he says, I am the door . So it seems that we should understand the door to be Christ. In answer to this, Chrysostom says that in this parable our Lord refers to himself both as the door and the shepherd; but this is from different points of view, because a door and a shepherd are different. [2] Now aside from Christ nothing is more fittingly called a door than Sacred Scripture, for the reasons given above. Therefore, Sacred Scripture is fittingly called a door.
1368 According to Augustine, the door is Christ, because one enters through him: "After this I looked, and lo, in heaven an open door!" (Rev 4:1). Therefore, any one who enters the sheepfold should enter by the door, that is, by Christ, and not by another way. [3]
Note that both the sheep and their shepherd enter into the sheepfold: the sheep in order to be secure there, and the shepherd in order to guard the sheep. And so, if you wish to enter as a sheep to be kept safe there, or as a shepherd to keep the people safe, you must enter the sheepfold through Christ. You must not enter by any other way, as did the philosophers who treated the principle virtues, and the Pharisees who established the ceremonial traditions. These are neither sheep nor shepherds because, as our Lord says, he who does not enter the sheepfold by the door , i.e., does not enter by Christ, but climbs in by another way, that man is a thief and a robber , because he destroys both himself and others. For Christ and no one else is the door into the sheepfold, that is, the multitude of the faithful: "We have peace with God through our Lord Jesus Christ" (Rom 5:1); "there is no other name under heaven given among men by which we must be saved" (Acts 4:12).
According to this exposition, the connection with what went before is made in this way: Because they said that they could see without Christ - "now that you say, 'We see'" - our Lord shows that this is not true, because they do not enter by the door. Thus he says, Truly, truly, I say to you�
It should be noted that just as one who does not enter by the door as a sheep cannot be kept safe, so one who enters as a shepherd cannot guard the sheep unless he enters by the door, namely, by Christ. This is the door through which the true shepherds have entered: "And one does not take the honor upon himself, but he is called by God, just as Aaron was" (Heb 5:4). Evil shepherds do not enter by the door, but by ambition and secular power and simony; and these are thieves and robbers: "They set up princes, but without my knowledge," that is, without my approval (Hos 8:5). Further, he says such a person climbs in by another way , because the door, namely, Christ, since it is small through humility - "Learn from me; for I am gentle and lowly in heart" (Matt 11:29) - can be entered only by those who imitate the humility of Christ. Therefore, those who do not enter by the door but climb in by another way are the proud. They do not imitate him who, although he was God, became man; and they do not recognize his lowering of himself.
1369 Now he considers the shepherd. First, he mentions the mark of the shepherd; secondly, he shows through signs that he is the shepherd (v 3).
1370 The mark of the true shepherd is to enter by the door, that is, by the testimony of Sacred Scripture. Thus Christ said: "Everything written about me in the Law of Moses and the prophets and the psalms must be fulfilled" (Lk 24:44). He is called a shepherd: "I am not troubled when I follow you as my shepherd" [Jer 17:16]; "He rebukes and trains and teaches them, and turns them back, as a shepherd his flock" (Sir 18:13).
But if the door is Christ, as Augustine explains it, then in entering by the door, he enters by himself. [4] And this is special to Christ: for no one can enter the door, i.e., to beatitude, except by the truth, because beatitude is nothing else than joy in the truth. But Christ, as God, is the truth; therefore, as man, he enters by himself, that is, by the truth, which he is as God. We, however, are not the truth, but children of the light, by participating in the true and uncreated light. Consequently, we have to enter by the truth which is Christ: "Sanctify them in the truth" (17:17); "If any one enters by me, he will be saved" (10:9). If one wishes to enter even as a shepherd, he must enter by the door, that is, Christ, according to his truth, will and consent. Thus we read in Ezekiel (24:23): "And I will set up over them one shepherd, my servant David, and he shall feed them." This is like saying: They must be given by me, and not by others or themselves.
1371 Now he mentions the signs of a good shepherd; and there are three. The first relates to the gatekeeper, and is that the good shepherd is let in by him. As to this he says, to him the gatekeeper opens . This gatekeeper, according to Chrysostom, is the one who opens the way to a knowledge of Sacred Scripture. [5] The first one to do this was Moses, who first received and established Sacred Scripture. And Moses opened to Christ, because as was said above: "If you believed Moses, you would believe me, for he wrote of me" (5:46).
Or, according to Augustine, the gatekeeper is Christ himself, because he brings us himself. [6] He says, "He opens himself who reveals himself, and we enter only by his grace." "For by grace you have been saved" (Eph 2:8). It does not matter if Christ, who is the door, is also the gatekeeper; for certain things are compatible in spiritual matters that cannot occur in physical reality. Now there seems to be a greater difference between a shepherd and a door than between a door and a gatekeeper. Therefore, since Christ can be called both a shepherd and a door, as was said, much more so can he be called a door and a gatekeeper. But if you prefer that someone other than Moses or Christ be the gatekeeper, then consider the Holy Spirit the gatekeeper, as Augustine says. [7] For it is the office of a gatekeeper to open the door, and it says below of the Holy Spirit that "He will guide you into all the truth" (16:13). And Christ is the door insofar as he is the Truth.
1372 The second sign relates to the sheep, and it is that they obey the shepherd. This is what he says, the sheep hear his voice . This is reasonable if the resemblance to a natural shepherd is considered: because just as sheep recognize the voice of their shepherd due to familiar experience, so righteous believers hear the voice of Christ: "O that today you would harken to his voice" (Ps 95:7).
1373 But what of the fact that many who are Christ's sheep did not hear his voice, as Paul; or that some who were not his sheep did here it, as Judas? One might reply that Judas was Christ's sheep for that time as to his present righteousness. And Paul, when he did not hear the voice of Christ, was not a sheep but a wolf; but when the voice of Christ came it changed the wolf into a sheep. This reply could be accepted if it were not contrary to a statement in Ezekiel (34:4): "The crippled you have not bound up, the strayed you have not brought back." It seems from this that even when they were crippled and strayed they were sheep. Therefore, one must say that here our Lord is speaking of his sheep not only according to their present righteousness but even according to their eternal predestination. For there is a certain voice of Christ that only the predestined can hear, i.e., "He who endures to the end" (Matt 10:22).
Again, he says, the sheep hear his voice , because they might offer as an excuse for their unbelief the fact that not only they, but none of the leaders believed in him. So he says in answer to this, the sheep hear his voice , as if saying: They do not believe because they are not my sheep.
1374 The third sign is taken from the actions of the shepherd. Here he mentions four actions of a good shepherd: the first being that he knows his sheep. He says, he calls his own sheep by name , which shows his knowledge of and familiarity with his sheep, for we call by name those whom we know familiarly: "I know you by name" (Ex 33:17). This is part of the office of a shepherd according to: "Be diligent to know the countenance of your flock" [Prv 27:23]. This applies to Christ according to his present knowledge, but even more so considering eternal predestination, by which he knew them by name from eternity: "He determined the number of the stars, he gives to all of them their names" (Ps 147:4); "The Lord knows those who are his" (2 Tim 2:19).
The second action of a good shepherd is that he leads them out , i.e., he separates them from the society of those who are evil: "He brought them out of darkness and gloom" (Ps 107:14).
The third is that having separated them from evil and having brought them into the sheepfold, he has brought out all his own , from the sheepfold. He does this, first, for the salvation of others: "I will send survivors to the nations" (Is 66:19); "Behold, I send you as sheep in the midst of wolves" (Matt 10:16), so that they can make sheep out of the wolves. Secondly, they are to show the direction and way to eternal life: "To guide our feet into the way of peace" (Lk 1:79).
Fourthly, the good shepherd goes before his sheep by the example of a good life; so he says, he goes before them , although this is not what the literal shepherd does, for he follows, as in "I took him from following the ewes" [Ps 78:70]. But the good shepherd goes before them by example, "not as domineering over those in your charge but being examples to the flock" (1 Pet 5:3). And Christ does go before them: for he was the first to die for the teaching of the truth - "If any man would come after me, let him deny himself and take up his cross and follow me" (Matt 16:24); and he went before all into everlasting life - "He who opens the breach will go up before them" (Mic 2:13).
1375 Now he considers the effect that both the thief and the shepherd have upon the sheep. First, he mentions the effect of the good shepherd; secondly, the effect of the wolf and the thief (v5).
1376 He says, first, that the sheep follow him who goes before them. This is easy to see, because subjects follow in the steps of their leaders, as is stated: "Christ also suffered for you, leaving you an example, that you should follow in his steps" (1 Pet 2:21); "My foot has held fast to his steps" (Job 23:11). The sheep follow for they know his voice , i.e., they know it and take delight in it: "Let me hear your voice, for your voice is sweet" (Song 2:14).
1377 The effect that the thief has is that the sheep do not follow him for very long, but only for a time; so he says, a stranger they will not follow , i.e., they do not follow a false and heretical teacher: "The children who are strangers have lied to me" [Ps 17:46]. Thus Paul did not follow false teachers for long. But they will flee from him , because "Bad company ruins good morals" (1 Cor 15:33). They flee for they do not know , that is, do not approve of, the voice of strangers , meaning their teaching, which spreads stealthily like a cancer.