For ask now about former ages, long before your own, ever since the day that God created human beings on the earth; ask from one end of heaven to the other; has anything so great as this ever happened or has its like ever been heard of? Has any people ever heard the voice of a god speaking out of a fire, as you have heard, and lived? Or has any god ever attempted to go and take a nation for himself from the midst of another nation, by trials, by signs and wonders, by war, by a mighty hand and an outstretched arm, and by terrifying displays of power, as the LORD your God did for you in Egypt before your very eyes?
He goes on, but you get the point. Israel had witnessed things that no one had ever seen before, and so, their ethics, laws, social structure, religion...everything, revolved not around ideas imagined out of the blue but around touchable, visible experience. As such, what the Israelites could not afford to forget or downplay was that experience.
Now, culture has changed over the past few thousand years. The Enlightenment tells us that such experiences are impossible, and so although we can value the ethos behind such mythology, we should intentionally forget the notion that such experiences actually occurred. At the risk of sounding very unenlightened, we do ourselves great harm by ignoring Moses's advice, just as the Israelites eventually did.
As Christians, our existence revolves around one tangible experience: the resurrection of Jesus. Not a spiritual resurrection, not a hallucination made up by the apostles due to over-abundant stress hormones, the infant Church grew and matured with the memory of a physically raised Savior. As Paul writes later, "If there is no resurrection of the dead, then Christ has not been raised; and if Christ has not been raised, then our proclamation has been in vain and your faith has been in vain." 2000 years later, it is no less a challenge for us to remember what God actually did then it was for the Hebrews to remember what God actually did. In fact, post Enlightenment, I would say it is much harder. After all, only fools and mental pygmies believe in the impossible. But if we listen to what our rivals would have us believe, thereby downplaying the importance of God's actual works, if not denying them all together, why should we expect an outcome any different than what the Israelites eventually experience: to become a lost, wandering people scattered among the nations?
As Christians, we must have the courage of Moses. We must be the ones who stand up and say, at least to each other, "Ask of the generations before you, of history long before your own, ever since time remembered, has such a great thing ever happened? Has the likes of it ever been heard of? Has any man ever been born of woman and God? Has a man ever come back from the grave three days after his death? Has any god ever attempted to take a nation for himself, not from just one other nation, but from multiple nations and peoples all around the globe, by suffering and crucifixion and sacrifice, and ultimately by the defeat of death itself? Since when has God ever chosen to dwell within his people, not in a temple, not in a tent, but within those who follow the one he sent. To us it was shown so that we would acknowledge that the Lord is God, and Christ is his Son."
Let us not be another generation of people who forget the words of Moses, who forget the mighty works of God to free us, who forget the reality of a risen Savior.
Stopping point: Deuteronomy 4