Small Historical Creed (Deuteronomy 6:20-25)
In summary the text is trying to communicate this advice or warning: Remember what the Lord has done.
It is all based on the question the Lord is suggesting that future generations will ask: "What is the meaning of the stipulations, decrees and laws the Lord our God has commanded you?" (Dt 6:20). In other words: what is our faith about? why we believe in this way?
The Lord suggest also the answer to the question. The living generation is committed to share what the Lord has done in the past for his people and remembering the past make them answer the question.
First they are especially reminded of leaving the Egypt. The experience of Egypt is very important for God's people. It reminds God's people that they were once slaves and only by his power and provision were freed (Dt 6:21). Their life was changed because of God. Without him there would be no people of God.
Second there is a perspective for them in establishing a different society based on obedient relationship with God. Not only because this is what the Lord wants but for the goodness (Dt 6:24) of the people. All of the commandments and words of God are the new way of life for the community.
So the final answer for the question stated above would be something like this: "we believe, we have faith, because the Lord cares for us and in seeking good for us he changed our lifes from certain misery and death to prosperity, so we can have a future again."