1 Corinthians 5:6; 1 Corinthians 9:15-16

6 Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump?
15 But I have used none of these things : neither have I written these things, that it should be so done unto me: for it were better for me to die , than that any man should make my glorying void . 16 For though I preach the gospel , I have nothing to glory of: for necessity is laid upon me; yea, woe is unto me, if I preach not the gospel !