Is. 49:1-7, 1 Cor. 1:18-31
Isaiah says that the Lord chose a servant from the womb to be a glorious weapon, His sword, His arrow. This servant would be Israel in whom He would be glorified. Israel had wandered away from God. Judah had been scattered. But the plan was for a new Israel to be born who would please the Lord and in so doing, He would raise up the tribes of Israel to new life. But not only this, but Isaiah says that God is going to be so pleased, so glorified and honored that it would be a shame to only save Israel and Judah, so He plans to make His servant shine in such a way that the kings and princes of the nations, the ends of the earth will see and bow themselves before the Lord.
This is what God did through His Son Jesus. He was born and kings came and bowed before Him. He rode into Jerusalem and many proclaimed Him king. He was crucified and soldiers confessed that truly He was the Christ. The thing to notice is that what made all of this effective and powerful in the first instance was that God was pleased. And this is why the preaching of the cross is the power of God. The cross is preached, when you share the gospel with a stranger, or remind your friend of the gospel – the power is not you getting all the words right. The power is in what pleases God. And He has chosen the weak things to overcome the strong. He has chosen the low and despised things to overcome the things that seem great and powerful.
Because Jesus was obedient, because He listened to the voice of God His Father, because He went into Jerusalem and faced what Israel and all men deserve to face, God is eternally and fully and unbreakably pleased with His Son, and God is so fiercely pleased with His Son, that all who trust in Him find themselves engulfed by that same pleasure. And so we boast in Him. He is our hero, our King. Our confidence is not in ourselves. It is not in our friends. It is not in being right. Our confidence is in the One who pleased God, and now eternally pleases God, and God is pleased to work through our weakness, to work through all who put their trust in Him.