“Know, therefore, that the Lord your God is not giving you this good land to possess because of your righteousness …” Deuteronomy 9:6
An immunization shot gives a weak form of a disease—not enough to do harm, but strong enough to cause our bodies to generate protective antibodies. In today’s reading, Moses implied that past sins, if confessed and learned from, can in a sense “immunize” us against future sins. The protection is not infallible, but the spiritual antibodies, as it were, formed by repentance can help keep us from similar or worse future sins, especially pride.
Instead, it’s all about God. He was the one leading Israel to victory. He was the one judging the wickedness of the Canaanites and decreeing their defeat. He was the one keeping His promises to the Patriarchs. There was no reason for the people to feel prideful.