They humbled his feet in fetters: the iron pierced his soul,

“Not nature but foolishness makes the slave. Not manumission but learning makes a person free. Esau was born free, but he became a slave; Joseph was sold into slavery, but he was raised to power8 so that he might rule those who had purchased him. Yet he did not slight his obligation to work zealously; he clung to the heights of virtue; he preserved the liberty of innocence, the stronghold of blamelessness. So the psalmist beautifully says, "Joseph had been sold into slavery. They had bound his feet with fetters." "He had been sold into slavery," he says; he did not become a slave. They had bound his feet, but not his soul.How is his soul bound when he says, "The iron pierced his soul"? Although the souls of others were pierced with sin (iron is sin, because it pierces within), the soul of blessed Joseph did not lie open to sin but pierced through sin. He was not swayed by the beauty of his mistress's charms, and so he did not experience the flames of passion, for he was aflame with the greater flame of divine grace. Thus, it is said very aptly of him, "Because the word of the Lord burned him," and with this he quenched the fiery darts of the devil.”

“Next he doth relate the story, mentioning what Joseph suffered in his low estate, and how he was raised on high. "His feet they hurt in the stocks: the iron entered into his soul, until his word came" (ver. 18). That Joseph was put in irons, we do not indeed read; but we ought no ways to doubt that it was so. For some things might be passed over in that history, which nevertheless would not escape the Holy Spirit, who speaketh in these Psalms. We understand by the iron which entered into his soul, the tribulation of stern necessity; for he did not say body, but "soul." There is a somewhat similar expression in the Gospel, where Simeon saith unto Mary, "A sword shall pierce through thy own soul also." That is, the Passion of the Lord, which was a fall unto many, and in which the secrets of many hearts were revealed, since their sentiments respecting the Lord were extorted from them, without doubt made His own Mother exceeding sorrowful, heavily struck with human bereavement. Now Joseph was in this tribulation, "until his word came," with which he truly interpreted dreams: whence he was introduced to the king, that unto him also he might foretell what would happen in respect to his dreams. But since he said, "Until his words were heard," that we might not altogether so understand "his," that any one might think so great an event was to be ascribed unto man; he at once added, "The word of the Lord inflamed him" (ver. 19); or, as other copies have it more closely from the Greek, "The word of the Lord fired him," that he also might be reputed amongst those to whom it is said, "Receive ye praise in His holy Name."”

“Whose feet they hurt with fetters,.... For it seems Joseph was not only cast into prison, upon the calumny of his mistress; but had fetters put upon him, and his feet were made fast with them; and these were so close and heavy, as to pinch and gall and hurt him; which, though not mentioned in his history, was undoubtedly true; see Gen 39:20. He was laid in iron: or "the iron" (or, as the Targum, "the iron chain") "went into his Soul" (f); his body; it ate into him, and gave him great pain: or rather, as it is in the king's Bible, "his soul went into the iron chain"; there being, as Aben Ezra observes, an ellipsis of the particle and which is supplied by Symmachus, and so in the Targum; that is, his body was enclosed in iron bands, so Buxtorf (g). In all this he was a type of Christ, whose soul was made exceeding sorrowful unto death: he was seized by the Jews, led bound to the high priest, fastened to the cursed tree, pierced with nails, and more so with the sins of his people he bore; and was laid in the prison of the grave; from whence and from judgment he was brought, Isa 53:8. (f) So Pagninus, Montanus, Vatablus. (g) Lexic. "in voce"”