1 Thou shalt say, therefore, in that day, I will praise thee, O Yahweh! Though thou hast been angry with me, Thine anger turneth back. And thou dost comfort me.
Jerome · AD 420 And you shall say on that day: I will praise you, O Lord, for you were angry with me, but your anger has turned away, and you have comforted me. Behold, God is my salvation; I will trust, and will not be afraid; for the Lord God is my strength and my song, and he has become my salvation.
Thomas Aquinas · AD 1274 384. I will confess. Here the thanksgiving for the benefit they received is set out, which indeed the prophet already saw by the prophetic spirit and promised to the people.
2 Lo, GOD is my salvation! I will trust and not dread,—For, my might and melody, is Yah, Yahweh, And he hath become mine, by salvation.
Bonaventure · AD 1257 This fortitude is from God redeeming through the incarnation of the divine Word. Whence Isaiah says: "The Lord is my strength and my praise, and he has become my salvation; you shall draw waters with joy from the fountains of the Savior." These are the waters in which the soul is strengthened, purified, redeemed, sanctified, and snatched from the power of demons.
Thomas Aquinas · AD 1274 386. Against the second evil, he confesses confidence in God: behold, God is my savior, freeing the people from the slavery of Babylon, or more truly, who will save his people: for he shall save his people from their sins (Matt 1:21); fear you not, my servant Jacob, says the Lord, neither be dismayed, O Israel: for behold, I will save you from a country afar off (Jer 30:10).
3 Therefore shall ye draw water, with rejoicing,—out of the fountains of salvation.
Ambrose of Milan · AD 397 Better is the foolishness that has eyes to see its own wounds than wisdom that does not have them. And therefore, with the gaze of his own foolishness, such a great king admits to being afflicted by miseries; so that he may find the remedy of repentance, which Judas, who possessed a field with the wages of iniquity, could not find.
Cassiodorus · AD 585 We say that God is … a fountain because he fills the thirsty and empty.
Thomas Aquinas · AD 1274 387. You shall draw. Here he promises the benefit: waters, of comfort, cooling them against the heat of tribulation. 391. It is to be noted on the words, you shall draw waters (Isa 12:3), that there is first, the water of doctrine, below: all you that thirst, come to the waters (Isa 55:1); second, of grace: he that believes in me, out of his belly shall flow rivers of living wa…
4 And ye shall say in that day, Praise Yahweh. Call upon his Name, Make known among the peoples, his doings,—Bring to remembrance that, exalted, is his Name!
Jerome · AD 420 (Verses 4, 5.) And you shall say on that day, confess the Lord and invoke His name: make His inventions known among the peoples: remember, for His name is exalted. Sing to the Lord, for He has done great things: announce this in all the earth.
Thomas Aquinas · AD 1274 388. And you shall say. Here he foretells that the people shall also sing, after the benefit has been received, and it contains the mutual exhortation of the people to divine praise. Exhortation to three things is set out: to the confession of divine praise, to thanksgiving: sing to the Lord (Isa 12:5), to shared rejoicing: rejoice (Isa 12:6).
5 Praise in song Yahweh, For a splendid thing, hath he done,—Well known, is this in all the earth.
Thomas Aquinas · AD 1274 389. Sing to the Lord. Here he exhorts them to thanksgiving; and first, that they give thanks to God: sing to the Lord, for he has done great things, in freeing us: sing to the Lord a new canticle: because he has done wonderful things (Ps 97[98]:1); second, that it be announced to the world: show this forth in all the earth: bless the God of heaven, give glory to him in the sig…
6 Make shrill thy voice and sing out thou inhabitress of Zion,—That great in the midst of thee, is the Holy One of Israel.
Jerome · AD 420 (Verse 6) Rejoice and praise, O dwelling place of Zion, for the Holy One of Israel is great among you. First, it must be said according to the letter: O dwelling place of Zion, rejoice and praise your God, for He who was once considered your God and was enclosed within the narrow bounds of the land of Judaea, now fills the whole earth with His knowledge.
Thomas Aquinas · AD 1274 390. Rejoice. Here the exhortation to exultation is set out; and first, that there be joy in their hearts: rejoice; second, that there be songs of joy in their mouths, praise; third, the reason for both is set out, for great is he, below: it shall rejoice with joy and praise (Isa 35:2). 394.