Isaiah 42:17Meaning & Commentary from the Church Fathers

Thus, having prophesied that the Gentiles would one day be summoned and would traverse paths unknown to them, and that darkness would yield to light, and the stubborn would turn to righteousness, the prophet’s words now unveil the ignorance of Israel's descendants, declaring, “But these have returned backward.” This statement specifically pertains to those who had been guided by divine law, were under My authority, and had Moses as their mediator, who had clearly heard, “The Lord thy God is one Lord, and only one Lord: that there shall be no one to be thy fathers but Mine” (Ex. 20:8). These very individuals have grievously turned back, while the Gentiles continue to harbor hope, having reverted to the impurities of Egypt and renewed the vice of ancient error. The reality of the parable was realized in them: a dog returned to its vomit, and a sow, after being washed, returned to wallowing in mud (2 Pet. 2:22). Our Lord Jesus Christ articulated a similar sentiment when speaking of Israel’s regressing to past unrighteousness: “When the unclean spirit goes out of a man, it goes through waterless places, seeking rest and finds none. Then it says, ‘I will return to my house from which I came.’ And upon arriving, it finds it empty, swept, and put in order. Then it goes and brings with it seven other spirits more wicked than itself, and they enter and dwell there; and the last state of that man becomes worse than the first” (Matthew 12:43-45). For they had served the gods of Egypt, and this wickedness was driven away when they were called to the knowledge of God through the law. Yet, they were again condemned, and their situation worsened when, while knowing the true God, they became apostates by honoring those who are not deities. Thus he declares shame upon you, who trust in the carved images and the esteemed names of idols, attributing glory to those crafted by human hands.