Psalms 69:2

"Fixed I am in the clay of the deep, and there is no substance." What called the clay? Is it those very persons that have persecuted? For out of clay man hath been made. But these men by falling from righteousness have become the clay of the deep, and whosoever shall not have consented to them persecuting and desiring to draw him to iniquity, out of his clay doth make gold. For the clay of the same shall merit to be converted into a heavenly form, and to be made associate of those of whom saith the Title of the Psalm, "in behalf of them that shall be changed." But at the time when these were the clay of the deep. I stuck in them: that is, they held Me, prevailed against Me, killed Me. "Fixed" then "I am in the clay of the deep, and there is no substance." What is this, "there is no substance"? Can it be that clay itself is not a substance? What is then, "fixed I am"? Can it be that Christ hath thus stuck? Or hath He stuck, and was not, as hath been said in the book of Job, "the earth delivered into the hands of the ungodly man"? Was He fixed in body, because it could be held, and suffered even crucifixion? For unless with nails He had been fixed, crucified He had not been. Whence then "there is no substance"? Is that clay not a substance? But we shall understand, if it be possible, what is, "and there is no substance," if first we shall have understood what is a substance. For there is substance spoken of even of riches, as we say, he hath substance, and he hath lost substance. ...God made man, He made substance; and O that he had continued in that which God made Him! If man had continued in that which God made him, in him would not have been fixed He whom God begot. […]

For it had previously been said through His passion that when He, according to the flesh, showed the example of humility, the waves of the sea raged against Him, to which He yielded willingly for us, so that the prophecy might be fulfilled: "I have come into deep waters, and the storm overwhelmed me." For He did not repel false witnesses nor the raging clamor of those shouting, "Crucify Him." He did not suppress the rabid hearts and mouths of the furious by force, but endured with patience. They did to Him all they wished; for He became obedient unto death, even the death of the cross. But after He rose from the dead, so that He might alone pray for the disciples established in the Church as in a ship, and carried by the faith of His cross as by wood, and endangered by the temptations of this world as by the waves of the sea, His name began to be honored in this world, in which He was despised, accused, and killed. So that He who had come in the flesh into the deep waters according to His passion, and had been overwhelmed by the storm, might now trample on the necks of the proud as the foam of the waves by the honor of His name.

He rather describes his untiring perseverance; and the same idea is expressed by his hoarse throat and failing eyes. He certainly did not cry out before men from mere affectation, nor was this hoarseness contracted in the course of one day. We perceive, then, that although his bodily senses failed him, the vigor of his faith was by no means extinguished.

I sink in deep mire, where there is no standing,....

This points at Christ's sufferings in his soul, and the inward agony he was in when he said, Now is my soul troubled; and, My soul is exceedingly sorrowful; for it was his soul that he made an offering for sin. And it instructs us, when we are in affliction, to commit the keeping of our souls to God, that we may be neither soured with discontent nor sink into despair.