"The LORD did not set his affection on you and choose you because you were more numerous than other peoples, for you were the fewest of all peoples. But it was because the LORD loved you." (Deuteronomy 7:7-8)
Moses commands the complete destruction of the seven nations of Canaan and their religious installations, and forbids intermarriage with them. He then names the ground of Israel's election: The LORD did not set his affection on you and choose you because you were more numerous than other peoples, for you were the fewest of all peoples. But it was because the LORD loved you and kept the oath he swore to your ancestors that he brought you out with a mighty hand and redeemed you from the land of slavery. The election is entirely from love and covenant faithfulness, not from anything in Israel that merited being chosen. The Catechism identifies this as the paradigm of all divine election: grace is always unmerited, always grounded in God's own love, never in the creature's worthiness (CCC 218).
God promises that if Israel keeps the covenant commands he will love them and bless them and multiply them with unparalleled abundance. He will keep away every disease. They are not to be afraid of the nations; they are to remember what God did to Pharaoh and to Egypt. He will send the hornet among their enemies. He will drive them out little by little, so that the land does not become desolate. Do not covet their silver or gold; it is detestable. Do not bring it into your house or you will be destroyed with it. The warnings about the contamination that accompanies idolatry are practical as well as theological: what we bring into our houses shapes us, for good or ill.
Brothers and sisters, the LORD loved you. Not because you were large or impressive or capable. Because he loved you. This is the only ground there is for divine election. Every effort to find in yourself the reason why God chose you will come up empty, because the reason is entirely in him. Receive that love without the need to explain it or deserve it. Just receive it.
Lord God, you chose us not because of our size or strength but because you loved us and kept the oath you swore to our ancestors. We did not earn this love and we cannot lose it by our smallness. Let us live from that chosen love with confidence and gratitude. Through Christ our Lord. Amen.