Adam Clarke on Deuteronomy 7:2

Thou shalt smite them, etc. - These idolatrous nations were to be utterly destroyed, and all the others also which were contiguous to the boundaries of the promised land, provided they did not renounce their idolatry and receive the true faith: for if they did not, then no covenant was to be made with them on any secular or political consideration whatever; no mercy was to be shown to them, because the cup of their iniquity also was now full; and they must either embrace, heartily embrace, the true religion, or be cut off.