I Corinthians 9:19, 22-24

19. Though I am free and belong to no man, I make myself a slave to everyone, to win as many as possible.

22. To the weak I became weak, to win the weak. I have become all things to all men so that by all possible means I might save some.
23. I do all this for the sake of the gospel, that I may share in its blessings.
24. Do you not know that in a race all the runners run, but only one gets the prize? Run in such a way as to get the prize.

2 Corinthians 3:2-6

2. You yourselves are our letter, written on our hearts, known and read by everybody.
3. You show that you are a letter from Christ, the result of our ministry, written not with ink but with the Spirit of the living God, not on tablets of stone but on tablets of human hearts.
4. Such confidence as this is ours through Christ before God.
5. Not that we are competent in ourselves to claim anything for ourselves, but our competence comes from God.
6. He has made us competent as ministers of a new covenant--not of the letter but of the Spirit; for the letter kills, but the Spirit gives life.

3 John v.4

4. I have no greater joy than to hear that my children are walking in the truth.