In the future, when your son asks you, "What is the meaning of the stipulations, decrees and laws the LORD our God has commanded you?" tell him: "We were slaves..." (Deuteronomy 6:20-21)
And for remainder of the chapter, Moses commands the nation of Israel to tell the following generations of how God rescued them and all the miraculous things they witnessed along the way. In other words, when the next generation asks "why do we do what we do?" tell them our incredible story of rescue. And it's almost as if Moses is saying, I know that it would be easier and more convenient to reply by saying "because I said so." But it's important that you take the time to tell them our story.
Moses must have known that the resigned response of "because I said so" would most likely only leave the next generation frustrated, ignorant and ultimately unlikely to follow the decrees and ways of Jehovah with any passion or personal commitment.
I think we would be wise to take Moses' sage advice ourselves when it comes to answering the questions of emerging generations.
So, in the future when (not if) the next generation asks "why do we do what we do?", tell them our incredible story of rescue.
We were slaves to sin, but God did some amazing stuff all along the way. Mainly he sent his son, Jesus, to die for our sins and now we're free. That's why we live lives that honor him and please him.
In the future, be sure to talk about the past. But don't do it because I said so:)