In this sermon, Moses takes as his text the people's memory of their experience in the wilderness, especially the harshness of those conditions when compared to the relatively lush surroundings of the promised land and God's miraculous provision of manna.
Essentially, Moses calls for Israel to remember their dependence upon God and reminds them that their faithful observance of the commandments is the proper way to foster that relationship. In God's plan, the difficulties of the wilderness prepared Israel for their life in the land by teaching them that nature alone cannot provide for their every need (vv. 1-6). Upon their arrival in the promised land, its relatively prosperous abundance will tempt Israel to forget their dependence upon God's nurture (vv. 7-17). Their proper response is to remember and to "thank" (literally "bless") the Lord their God (vv. 18-20).
The sermon in its entirety (the lectionary utilizes only a snippet) has a concentric arrangement illustrative of its message:
A Observe the commandments and prosper (v. 1)
B "Remember the long way that the LORD your God has led you" (v. 2a)
C The wilderness and the manna (vv. 2b-6)
D Prosperity in the land (vv. 7-10)
X "Do not forget the LORD your God" (v. 11)
D′ Prosperity in the land (vv. 12-14)
C′ The wilderness and the manna (vv. 15-17)
B′ "Remember the LORD your God" (v. 18)
A′ "Forget the LORD…and…you shall surely perish" (vv. 19-20)
The paired sections are tied together with repeated vocabulary (in Hebrew, at least; NRSV translations vary):
In this way, the sermon encapsulates a major theme of the book, namely the principle of retributive justice in which, stated somewhat crassly, obedience brings blessing (as seen in verses 1-10) and disobedience brings judgment (as seen in verses 12-20). It is best to "take care that you do not forget the LORD your God" (v. 11).
7For the Lord your God is bringing you into a good land, a land with flowing streams, with springs and underground waters welling up in valleys and hills, 8a land of wheat and barley, of vines and fig trees and pomegranates, a land of olive trees and honey, 9a land where you may eat bread without scarcity, where you will lack nothing, a land whose stones are iron and from whose hills you may mine copper. 10You shall eat your fill and bless the Lord your God for the good land that he has given you.
11 Take care that you do not forget the Lord your God, by failing to keep his commandments, his ordinances, and his statutes, which I am commanding you today. 12When you have eaten your fill and have built fine houses and live in them, 13and when your herds and flocks have multiplied, and your silver and gold is multiplied, and all that you have is multiplied, 14then do not exalt yourself, forgetting the Lord your God, who brought you out of the land of Egypt, out of the house of slavery, 15who led you through the great and terrible wilderness, an arid waste-land with poisonous* snakes and scorpions. He made water flow for you from flint rock, 16and fed you in the wilderness with manna that your ancestors did not know, to humble you and to test you, and in the end to do you good. 17Do not say to yourself, My power and the might of my own hand have gained me this wealth. 18But remember the Lord your God, for it is he who gives you power to get wealth, so that he may confirm his covenant that he swore to your ancestors, as he is doing today.
New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org