Charles H. Spurgeon on Psalms 78:5

For he established a testimony in Jacob. The favoured nation existed for the very purpose of maintaining God's truth in the midst of surrounding idolatry. Theirs were the oracles, they were the conservators and guardians of the truth. And appointed a law in Israel, which he commanded our fathers, that they should make them known to their children. The testimony for the true God was to be transmitted from generation to generation by the careful instruction of succeeding families. We have the command for this oral transmission very frequently given in the Pentateuch, and it may suffice to quote one instance from De 6:7: "And thou shalt teach them diligently unto thy children, and shalt talk of them when thou sittest in thine house, and when thou walkest by the way, and when thou liest down, and when thou risest up." Reader, if you are a parent, have you conscientiously discharged this duty?