2 Corinthians 1:17-19

17When I therefore was thus minded, did I use lightness? or the things that I purpose, do I purpose according to the flesh, that with me there should be yea yea, and nay nay?

18But as God is true, our word toward you was not yea and nay.

19For the Son of God, Jesus Christ, who was preached among you by us, even by me and Silvanus and Timothy, was not yea and nay, but in him was yea.