Matthew 5:37

But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil.
— Matthew 5:37, King James Version

In other translations

World English Bible (WEB)

But let your speech be, 'Yes, yes; No, no.' Whatever is more than these is of the evil one.

American Standard Version (ASV)

But let your speech be, Yea, yea; Nay, nay: and whatsoever is more than these is of the evil one.

Young's Literal Translation (YLT)

but let your word be, Yes, Yes, No, No, and that which is more than these is of the evil.