What does Deuteronomy 9:5 mean?

You’re not going in to take their land because you’re righteous or have your act together. It’s because those nations are so wicked, and because God is keeping the promise he made to your ancestors—Abraham, Isaac, and Jacob. Deuteronomy 9:5 - Modern Text Bible

(He repeats the point: this isn’t a reward for Israel’s goodness, but God keeping his word and judging evil.)