You are a people for his own possession: see the same expression in 7.6; 14.2.

You are to keep all his commandments: there is a lot of repetition in this section, emphasizing the importance of these instructions.

An alternative translation model combining verses 17 and 18 may be:

• Today you have acknowledged [or, confessed] that Yahweh will be your God. You have promised to walk in his paths, to keep all his laws, and do all he commands you. Since you have agreed to keep all his commands, on his part Yahweh has agreed that you will be his own people.

Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on Deuteronomy. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .