To look at Paul's circumstances, one would think that God was very displeased with his service. This would certainly have been the case if Paul was living under the law of Israel. Paul's evaluation of his service was not based upon his physical circumstances. It was based upon comparing his service with the revealed will of God in His Word. Doing a work of faith, not looking to circumstances for guidance or confirmation of our faith, is a principle that will allow us to function as the mature adult sons that God has made us in Christ.
Charity is the act that grows out of love.
There can be no true act of charity without love and there can be no true love without it producing an act of charity. In God's dealing with the nation Israel under the law, God motivated His people to service through fear, a fear of judgement and of the loss of blessing. This motivation by fear can be seen both in the nation Israel and in the Gentile nations that saw the mighty works that God did for the them. And I will surely hide my face in that day for all the evils which they shall have wrought, in that they are turned unto other gods. In addition to the fear that was generated in the nation Israel, the mighty works that God did in Israel were to bring fear to the Gentile nations.