Ye do the deeds of your father. — It is better to read works rather than “deeds,” as in John 8:39. They did not the works of Abraham. They did the works of that father, who is now more clearly pointed out, but still not named. Before, when he was referred to (John 8:38), they could answer that Abraham was their father; but their works prove that they are not the true children of Abraham (John 8:39-40). They see that a spiritual father is intended, and they will claim God as their Father.
We be not born of fornication. — The meaning of this is to be found in the fact that the word became in the Old Testament prophets a frequent symbol for idolatry. Comp. Isaiah 1:21; Jeremiah 2:20; Jeremiah 3:8-9; Ezekiel 16; Hosea 1:2 (especially), 4:12, and 5:7.) They, as distinguished from the nations among whom they dwelt, had maintained a pure monotheism, and had never been idolaters, or children born of spiritual fornication.
We have one Father, even God. — “We” is strongly emphatic, expressing their pride in the theocracy, and their spiritual superiority to other nations. There may be in this pride also a touch of the scorn with which they asked “Will He go unto the dispersion of the Gentiles?” (John 7:35), or with which they call Him a Samaritan, as they do in this very discussion (John 8:48). “Howbeit every nation made gods of their own, and put them in the high places which the Samaritans had made, every nation in their cities wherein they dwelt.” This is the historian’s account of the spiritual paternity of the Samaritans, and these Jews may well have felt their superiority in contrast with their neighbours. (See the whole passage in 2 Kings 17:26-41, especially John 8:30-31.)