“ And I gave you a land for which you did not labour, and cities which you did not build, and you dwell in them. From vineyards and oliveyards, which you did not plant, you eat.”
This was a reminder of the specific promises that it would be so (Deuteronomy 6:10-11). Land already prepared for sowing, cities already built, for living in, and vineyards and oliveyards already planted, for eating from.
So ends the preamble that describes what the Great Deliverer has done for them, and what He has given them. Now will follow his requirements as was normal in a suzerainty treaty of that time. It is noteworthy that what we call the ten commandments (Exodus 20:1-17); The Book of Deuteronomy; and this passage here are all more or less based on the pattern of Hittite suzerainty treaties, which began with the name and titles of the Suzerain, a preamble declaring what the Suzerain had done for the people (they called their conquest a deliverance), followed with details as to his requirements and the necessity for rejecting his enemies, the writing down of the treaty to be read periodically, and often ending with blessings and cursings.