Original Verse:
1st Corinthians Chapter 9 Verse 18What then is my reward? That, when I preach the gospel, I may make the gospel without charge, so as not to use to the full my right in the gospel.

Reference Verses:
2nd Corinthians Chapter 12 Verse 14Behold, this is the third time I am ready to come to you; and I will not be a burden to you: for I seek not yours, but you: for the children ought not to lay up for the parents, but the parents for the children.
2nd Corinthians Chapter 11 Verse 7Or did I commit a sin in abasing myself that ye might be exalted, because I preached to you the gospel of God for nought?
2nd Corinthians Chapter 12 Verse 13For what is there wherein ye were made inferior to the rest of the churches, except [it be] that I myself was not a burden to you? forgive me this wrong.