2 Corinthians 12:9

But he said to me, "My grace is sufficient for you, for my power is made perfect in weakness." Therefore I will boast all the more gladly of my weakness, so that the power of Christ may rest upon me.

(v9, ESV)

This is such an awesome verse. What sweet words these are that are from our Lord. Grace is giving to someone something that they do not deserve. So, what we receive from the Lord that we do not deserve is enough. Paul was pleading and asking to be rid of his thorn in the flesh. He was asking but not realizing that he has already received more that enough. He is reassured that he already has more than he needs. Though we should ask and we continue to ask, sometimes this is God's answer. He reveals to us that we already have the tools for the job. We are shown that God has already equipped us with all we need.

His power is made perfect in our weakness. How does that work?

but God has chosen the foolish things of the world to shame the wise, and God has chosen the weak things of the world to shame the things which are strong,

(1 Corinthians 27, NASB)

This is one way in which the power of God is made perfect in our weakness. We who are weak or considered weak to others are used by God. When the weak are used powerfully by God to shame the strong, it reveals God's power. The weak overcoming the strong can sometimes be unexplainable. In these cases, God shines as the only explanation for why the weak has just shamed the strong. This is not so that we will get the glory or boast in ourselves. This is for God to get the glory.