Then it shall come about when the Lord your God brings you into the land which He swore to your fathers, Abraham, Isaac and Jacob, to give you, great and splendid cities which you did not build, and houses full of all good things which you did not fill, and hewn cisterns which you did not dig, vineyards and olive trees which you did not plant, and you eat and are satisfied, then watch yourself, that you do not forget the Lord who brought you from the land of Egypt, out of the house of slavery.
Deuteronomy is a series of three "sermons" by Moses on the plains of Moab before the people enter the land. In each sermon, Moses is reminding the people of what God has done and wants them to do. You can sense that the people are not getting it like they should. Still, Moses is relentless in depicting God's gracious dealings with them.
Later, in Dt 30, Moses says that he has set before them life or death and blessing or curse. He pleads with them to choose life/blessing. In Dt 31, God pulls Moses aside and essentially tells him that the people are going to choose death/curse over life/blessing. They are going to forget and neglect the grace of God. They will not remember the extent of His promises to their fathers. They will will not cherish that He brought them up out of bondage and freed them.
What is even more bothersome is the fact that in the land, they persist in this. Then, under their judges, they become even more selfish [Jdgs 21.25]. Under their kings, the nation is divided! When the prophets preach, they don't listen. And when their Messiah comes, many reject Him.
Of course, we are never like this?
But there is something different about this New Covenant grace in which we stand. We don't necessarily get it all the time [see Apostle Peter], but we have been given the Spirit in a way that they had not. God's covenant people are no longer physically, ethnically, and/or geographically defined. So now, by the Spirit and because of the work of the Messiah, we, as his people, can now see and experience further grace when we don't fully understand grace. There is something humbling, odd, sweet, and dangerous about that. This kind of grace must birth faith, hope, and love. This kind of grace does not yield apathy, passivity, and pride.
May it be so with us.