II. Witness is produced against them, one instead of a thousand; it is God's omniscience (v. 3): I know Ephraim, and Israel is not hidden from me. They have not known the Lord (v. 4), but the Lord has known them, knows their true character however disguised, knows their secret wickedness however concealed. Note, Men's rejecting the knowledge of God will not secure them from his knowledge of them; and when he contends with them he will prove their sins upon them by his own knowledge, so that is will be in vain to plead Not guilty.