I will multiply your descendants as the stars of heaven is the same wording as used in 22.17. And will give … lands is a repetition of verse 3b, which most translations retain as emphasizing the gift of the land. If its repetition has a different meaning, an appropriate adjustment should be made.

And by your descendants all the nations of the earth shall bless themselves: for the parallel expression and discussion see 22.18.

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .