Charles Ellicott Commentary Jeremiah 2:5

"thus saith Jehovah, What unrighteousness have your fathers found in me, that they are gone far from me, and have walked after vanity, and are become vain?" — Jeremiah 2:5 (ASV)

Vanity: In the special sense, as a synonym for idol-worship (Deuteronomy 32:21; 1 Kings 16:13). As in the character of a husband wronged by his wife’s desertion Jehovah pleads with His people, and asks whether He has failed in anything.