Set thy bounds. These boundaries were not reached until 400 years later, under David and Solomon (1 Kings 4:21, 24; 2 Chron. 9:26). Moses here confirms God’s promise to Abraham (Gen. 15:18). Inasmuch as Solomon was “a man of rest” (1 Chron. 22:9), the work of empire building must have been accomplished by David (2 Sam. 8:3–15; 10:6–19; 1 Kings 5:3; 1 Chron. 22:8).
The river. That is, the Euphrates, pre-eminently “the river” of OT times (see Gen. 15:18; Deut. 1:7).
Drive them out. Many of the Canaanites were no doubt forced northward, and may have united with the Hittite kingdom, which for many centuries formidably opposed the Egyptian and Assyrian empires.