Deuteronomy 32:6-7 -

Instead of gratefully acknowledging the Divine beneficence, and dutifully obeying the Divine will, Israel had perversely and foolishly requited the Lord for all his benefits, by apostasy from him. Do ye thus requite? The verb here signifies primarily to do to any one either good or evil, whether in return for what he has done or not (cf. Genesis 1:15 ; 1 Samuel 24:18 ; Proverbs 3:30 ); then, as a secondary meaning, to reward, repay, requite, as here and Psalms 18:21 . To bring more forcibly to their view the ingratitude and folly of their conduct, Moses dwells upon what God was and had been to the nation: their Father , in that he had, in his love, chosen, them to be his people (cf. Isaiah 63:16 ; Isaiah 64:7 ; Malachi 2:10 ); their Purchaser , who had acquired possession of them by delivering them out of Egypt (cf. Psalms 74:2 ); their Maker, who had constituted them a nation; and their Establisher , by whom they had been conducted through the wilderness and settled in Canaan. Days of old ; the times of Israel's deliverance from bondage, and the times during which successive generations had lived and experienced the goodness of the Lord. The form of the word rendered "days" is poetical, and is found only here and in Psalms 90:15 , which is also ascribed to Moses. The years of many generations ; literally, years of generation and generation ; " aetatum singularum annos " (Rosenmüller).