Matthew 5:36

New King James Version

Nor shall you swear by your head, because you cannot make one hair white or black.

See the chapter Copy

And which of you by worrying can add one cubit to his stature?

Which of you by worrying can add one cubit to his stature?

nor by the earth, for it is His footstool; nor by Jerusalem, for it is the city of the great King.

But let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No.’ For whatever is more than these is from the evil one.