from the desert to the Euphrates: See Genesis 15:18; Numbers 34:2–12; Deuteronomy 11:24; 2 Chronicles 9:26.
I will deliver the inhabitants: God promised the land to Abraham (Genesis 15:16). At that time, "the iniquity of the Amorites" was not yet complete. Now they were. God was not randomly taking land from the Amorites (that is, the Canaanites). He used the Israelites to judge their wickedness.