Every generation sees it: children who grow up in the faith, then abandon it for something else (or, these days, for nothing at all) when they become adults.
Even God anticipated this would happen. In the early verses of Deuteronomy chapter eleven, the Lord reminds Israel twice that their descendants (children) would not be the witnesses of all they had seen. Because the children had not been witnesses to the faith building works of God, the faith of Israel’s future generations would be inevitably less than that of their forebears.
Unless parents were intentional and persistent in passing on the faith to their children. In the middle of the chapter God advises: “Teach them [God’s words] to your children, talking about them when you sit at home and when you walk along the road, when you lie down and when you get up.”
There were serious reasons for such religious focus: “so that you may live and prosper and prolong your days” (Deuteronomy 5:33), that God might keep you alive (6:24) and grant you “abundant prosperity” (28:11).
Well-being, your own and that of your children, was (and is) directly connected to obeying the requirements, decrees, laws, and commands (all words used in chapter eleven) of God. Obedience to God must be a hallmark of your life. Recognition for all God has done for you and expressed gratitude for each blessing must be two others. Visible trust in God, confidence in Him and dependence on Him are three more. These six characteristics must be a part of your life for your own good. They must be seen in your life by your children as their example. You must cultivate them in the lives of your children for their own well-being.
When we are genuinely convinced God means what He says in these verses, our lives will be different, our future will be different, and so will be the lives and future of our children, because we will give attention to making them different.