“to show that this all-surpassing power is from God and not from us.”(2 Cor. 4:7)
Aside from the contrast between the great treasure and its cheap containers, we also see the contrast between the power of God and the fragility of these clay vessels. God shows his power when we are weak.
We have an Old Testament precedent for this. In Gideon’s time, Israel was getting ready for battle against the Midianites. They initially assembled an army of 32,000. The Midianite forces outnumber them with 135,000 warriors.
But what did God say?
"You have too many men for me to deliver Midian into their hands. In order that Israel may not boast against me that her own strength has saved her, announce now to the people, `Anyone who trembles with fear may turn back and leave Mount Gilead.' (Judges 7:2-3 )
Immediately, 22,000 left. But God was not satisfied. He further trimmed it down to 300. The ratio is now 450 to 1. One soldier against a batallion! The message will be clear that Israel’s victory will not be because of their might, but because of God.
If you want credit for yourself, then God will not be pleased to use you. He wants to engrave in your heart that power belongs to him, not you.
That is why God actively exposes the vulnerability of his servants. He arranges the circumstances of his servants in a way that exposes their weakness forcing them to rely solely in him. The passive voice in verse 11 (“always being given over to death” NIV)shows that someone else is actively arranging our circumstances, and it is God.
Perhaps, the super-apostles, like some today, taught that adversity has no place for those who are anointed. So in 12:12, Paul reminded them that the signs of an apostle: miracles signs and wonders were manifested in his ministry. So he is not inferior when it comes to anointing. But when it comes to listing his credentials, he shows them his sufferings (2 cor. 11:25ff.) He was not boasting about his exploits, he was telling them about how weak he is (11:30). And if you will move to chapter 12, he boasts about a prayer denied!!! Three times he asked for a thing, and three times God said "No". Why? Because his grace is sufficient and his power is made perfect in weakness (2 Cor. 12:7-9)