Know therefore that the LORD your God himself is God, the faithful God, who keeps covenant and loving kindness with them who love him.
Notice who is being described here, and in what order. Moses does not begin with what the people must do. He begins with what God is. Before a single instruction about loving him or keeping his commandments, there is a statement about his character, and the word he reaches for is faithful.
That order is deliberate, and it is why gratitude in Scripture does not depend on circumstances. If God’s faithfulness were a response to ours, it would rise and fall with our performance. Moses says it reaches to a thousand generations, which is his way of saying it does not run out.
He was speaking to people standing at the edge of a land they had not yet entered. They could see the promise and not yet the fulfilment. That is exactly the moment when a person needs to know that the One who made the promise is the kind of God who keeps it.