Matthew 5:36

Nor should you swear by your head, since you cannot make a single hair either white or black.

Matthew 6:27

But which of you, by being anxious, can prolong his life a single moment?

Matthew 23:16-21

Alas for you, you blind guides! You say 'if any answer by the Temple, his oath counts for nothing; but, if any one swears by the gold of the Temple, his oath is binding him'!

Luke 12:25

But which of you, by being anxious, can prolong his life a moment?

Treasury of Scripture Knowledge

Summary

Neither shalt thou swear by thy head, because thou canst not make one hair white or black.

General references

Bible References

Shalt

Matthew 23:16
Alas for you, you blind guides! You say 'if any answer by the Temple, his oath counts for nothing; but, if any one swears by the gold of the Temple, his oath is binding him'!

Because

Matthew 6:27
But which of you, by being anxious, can prolong his life a single moment?
Luke 12:25
But which of you, by being anxious, can prolong his life a moment?

General references

Luke 12:25
But which of you, by being anxious, can prolong his life a moment?