2 Corinthians 8:2

8:2 How that in a great trial of affliction the abundance of their joy and their deep poverty abounded unto the riches of their liberality.

2 Corinthians 8:8

8:8 I speak not by commandment, but by occasion of the forwardness of others, and to prove the sincerity of your love.

2 Corinthians 8:22

8:22 And we have sent with them our brother, whom we have oftentimes proved diligent in many things, but now much more diligent, upon the great confidence which [I have] in you.