19 He says then, “But I as a deaf man heard not”. He who replied not to what He heard, did, as it were, not hear them. “But I as a deaf man heard not. And I was as a dumb man that opens not his mouth.” And he repeats the same things again.
“And I became as a man that hears not, and in whose mouth are no reproofs”. As if He had nothing to say unto them, as if He had nothing wherewith to reproach them. Had He not already reproached them for many things? Had He not said many things, and also said, “Woe unto you, Scribes and Pharisees,” and many things besides? Yet when He suffered, He said none of these things; not that He had not what to say, but He waited for them to fulfil all things, and that all the prophecies might be fulfilled of Him, of whom it had been said, “And as a sheep before her shearer is dumb, so opens He not His mouth.” It behooved Him to be silent in His Passion, though not hereafter to be silent in Judgment. For He had come to be judged, then, who was hereafter coming to judge; and who was for this reason to come with great power to judge, that He had been judged in great humility.
20. “For in You, O Lord, do I hope; You will hear, O Lord, my God”. As if it were said to Him, “Why did you not open your mouth? Why did You not say, 'Refrain'? Why did You not rebuke the unrighteous, while hanging on the Cross?” He goes on and says, “For in You, O Lord, do I hope; Thou, O Lord my God, wilt hear.” He warns you what to do, should tribulation haply befall. For you seek to defend yourself, and perhaps your defence is not listened to by any one. Then are you confounded, as if you had lost your cause; because you have none to defend or to bear testimony in your favour. “Keep” but your “innocence” within, where no one can pervert your cause. False-witness has prevailed against you before men. Will it then prevail before God, where your cause has to be pleaded? When God shall be Judge, there shall be no other witness than your own conscience. In the presence of a just judge, and of your own conscience, fear nothing but your own cause. If you have not a bad cause, you will have no accuser to dread; no false-witness to confute, nor witness to the truth to look for. Do but bring into court a good conscience, that you may say, “For in You, O Lord, do I hope; Thou, O Lord my God, wilt hear.”
21. “For I said, Let not mine enemies ever rejoice over me. And when my feet slip, they magnify themselves against me”. Again He returns to the infirmity of His Body: and again the Head takes heed of Its “feet.” The Head is not in such a manner in Heaven, as to forsake what It has on earth; He evidently sees and observes us. For sometimes, as is the way of this life, our feet are “turned aside,” and they slip by falling into some sin; there the tongues of the enemy rise up with the bitterest malignity. From this then we discern what they really had in view, even while they kept silence. Then they speak with an unsparing harshness; rejoicing to have discovered what they ought to have grieved for. “And I said, Lest at any time my adversaries should rejoice over me.” I said this indeed; and yet it was perhaps for my correction that You have caused them to “magnify themselves against me, when my feet slipped;” that is to say, when I stumbled, they were elated, and said many things. For pity, not insult, was due from them to the weak; even as the Apostle speaks: “Brethren, if a man be overtaken in a fault, you which are spiritual restore such an one in the spirit of meekness;” and he combines the reason why: “considering yourself also, lest you also be tempted.” Not such as these were the persons of whom He speaks: “And when my feet slipped, they rejoiced greatly against me;” but they were such as those of whom He says elsewhere: “They that hate me will rejoice if I fall.”
22. “For I am prepared for the scourges”. Quite a magnificent expression; as if He were saying, “It was even for this that I was born; that I might suffer.” For He was not to be born, but from Adam, to whom the scourge is due. But sinners are in this life sometimes not scourged at all, or are scourged less than their deserts: because the wickedness of their heart is given over as already desperate. Those, however, for whom eternal life is prepared, must needs be scourged in this life: for that sentence is true: “My son, faint not under the chastening of the Lord, neither be weary when you are rebuked of Him.” “For whom the Lord loves He chastens, and scourges every son whom He receives.” Let not mine enemies therefore insult over me; let “them not magnify themselves;” and if my Father scourges me, “I am prepared for the scourge;” because there is an inheritance in store for me. You will not submit to the scourge: the inheritance is not bestowed upon you. For “every son” must needs be scourged. So true it is that “every son” is scourged, that He spared not even Him who had no sin. For “I am prepared for the scourges.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)