Matthew 5:36

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

Matthew 6:27

And which of you by being anxious can add one cubit unto the measure of his life?

Matthew 23:16-21

Woe unto you, ye blind guides, that say, Whosoever shall swear by the temple, it is nothing; but whosoever shall swear by the gold of the temple, he is a debtor.

Luke 12:25

And which of you by being anxious can add a cubit unto the measure of his life?

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
Woe unto you, ye blind guides, that say, Whosoever shall swear by the temple, it is nothing; but whosoever shall swear by the gold of the temple, he is a debtor.

Because

Matthew 6:27
And which of you by being anxious can add one cubit unto the measure of his life?
Luke 12:25
And which of you by being anxious can add a cubit unto the measure of his life?

General references

Luke 12:25
And which of you by being anxious can add a cubit unto the measure of his life?

American Standard Version Public Domain