He also designates temptation through the striking of the flood, when he adds: The flood struck against that house, namely as regards interior temptation, namely of fear, or sorrow, or joy, or love; Nahum 2: "The gates of the rivers are opened"; which indeed happens when temptations enter within, so that one may cry out that word of the Psalm: "Save me, O God, for the waters have come in even unto my soul." - But these temptations do not prevail against the observers of the divine commandments; on account of which it is added: And it could not move it: Proverbs 10: "As a passing tempest, so the wicked shall be no more, but the just is as an everlasting foundation"; in the Psalm: "Perfect my steps in your paths, that my footsteps be not moved." - But the reason for this stability is given when it is added: For it was founded upon firm rock. Hence it is said of the just man in Isaiah 22: "I will fasten him as a peg in a sure place." This fastening indeed is through charity: Romans 8: "Who shall separate us from the charity of Christ? Tribulation? or distress? or famine? or nakedness? or danger? or persecution? or the sword?" The fruit of true obedience, therefore, is victory over exterior and interior temptation through the power of a stable foundation.
109. (Verse 49.). But he who hears and does not do. Here, after the commendation of the truly obedient, he adds the reproach of the negligent, setting forth first the vice of the negligent, then adding the danger, and appending the downfall.
He therefore sets forth first the vice of the negligent, when he says: But he who hears and does not do, like Balaam, Numbers 24: "He said who is a hearer of the words of God, who knows the doctrine of the Most High."
This one is blameworthy, which he shows through a comparison, when he adds: He is like a man building his house upon the ground without a foundation. He calls ground a place that is inconstant and easily movable, according to that word of the Psalm: "Not so the wicked, not so, but like the dust which the wind casts from the face of the earth"; Isaiah 24: "The earth shall be utterly broken, the earth shall be crushed to pieces, and it shall be taken away like the tent of one night"; Job 4: "How much more those who dwell in houses of clay, who have an earthly foundation, are consumed as if by a moth." And this is because they are not "rooted in charity," but in earthly cupidity: Wisdom 4: "Adulterous plantings shall not give deep roots."
110. He adds the peril of the negligent person in the crashing of floods, when he adds: Against which the river crashed, that is, temptation driving forward, from which the peril of ruin threatens: Ezekiel thirteen: "Say to those who plaster the wall without mortar, that the wall shall fall. For there shall be an overflowing rain, and I will send great hailstones falling from above and a stormy wind breaking through." Of such persons, Isaiah twenty-eight: "When the overflowing scourge shall pass through, you shall be trodden down by it; whenever it passes through, it shall take you." For these are those of whom it is said below in chapter eight: "They believe for a time, and in the time of temptation they fall away"; and these are those "who have no roots."
111. Lastly he subjoins the downfall of the negligent person, when he says: And immediately it fell, and the ruin of that house was great: Zechariah fourteen: "There shall be the ruin of the horse and the mule, the camel and the ass and all the beasts of burden," that is, of all men who are brutish and negligent and impious; Zephaniah one: "Thus says the Lord: I will gather man and beast, I will gather the birds of the heavens and the fish of the sea; and the wicked shall have ruins, and I will destroy men from the face of the earth." Nor is this surprising, because, Proverbs four, "the way of the wicked is dark: they know not where they stumble."
From the peril therefore and the censure of the negligent and the commendation of the obedient, one is sufficiently invited to diligence in what is to be done, and in this the divine teachings reach their conclusion.