God chose Israel not because they were a mighty people, nor because there was anything inherently good. Go chose Israel to glorify Himself and to display His love.
(Deu 7:6-9 NKJV) For you [are] a holy people to the LORD your God; the LORD your God has chosen you to be a people for Himself, a special treasure above all the peoples on the face of the earth. The LORD did not set His love on you nor choose you because you were more in number than any other people, for you were the least of all peoples; but because the LORD loves you, and because He would keep the oath which He swore to your fathers, the LORD has brought you out with a mighty hand, and redeemed you from the house of bondage, from the hand of Pharaoh king of Egypt. Therefore know that the LORD your God, He [is] God, the faithful God who keeps covenant and mercy for a thousand generations with those who love Him and keep His commandments;
Also see Romans 9:10-12.
God chose Abraham and Sarah to be the parents of a nation. But Sarah was barren. God did this to show His power (Gen 18:9-19).
God chose Gideon to lead an army. But reduced the army to such a small number (the least) so that God would get the glory (Judges 7).
God chose David, to be King of Israel, even though he was the youngest of the “Jesse boys,” Jesse did not even present David to Samuel at first (1 Sam 16:1-13).
God chose a Pharisee named Saul (later renamed Paul, to be the Apostle to the Gentiles. Remember that before Damascus, Paul was not a friend to Gentile or to Christian. By the inspiration of the Holy Spirit, Paul called himself “the least of the apostles” (1 Cor 15:9) and “the least of all the saints” (Eph 3:8).