He'll use the weak to overcome the strong.

1 Cor 1:27-28
"God chose what is foolish in the world to shame the wise; God chose what is weak in the world to shame the strong; God chose what is low and despised in the world, even things that are not, to bring to nothing things that are"

Once Saint Francis of Assisi was confronted by a brother who asked him repeatedly, "Why you? Why you?"
Francis responded, in today's terms "why me what?"
"Why does everyone want to see you? Hear you? Obey you? You are not all so handsome, nor learned, nor from a noble family. Yet the world seems to want to follow you," the brother said.
Then Francis raised his eyes to heaven,knelt in praise to God, and turned to his interrogator:

"You want to know? It is because the eyes of the Most High have willed it so. He continually watches the good and the wicked, and as His most holy eyes have not found among sinners any smaller man, nor any more insufficient and sinful, therefore He has chosen me to accomplish the marvelous work which God has undertaken; He chose me because He could find none more worthless, and He wished to confound the nobility and grandeur, the strength, the beauty, and the learning of this world."