Matthew 5:36

You may not take an oath by your head, because you are not able to make one hair white or black.

Matthew 6:27

And which of you by taking thought is able to make himself a cubit taller?

Matthew 23:16-21

A curse is on you, blind guides, who say, Whoever takes an oath by the Temple, it is nothing; but whoever takes an oath by the gold of the Temple, he is responsible.

Luke 12:25

And which of you by taking thought is able to make himself any taller?

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
A curse is on you, blind guides, who say, Whoever takes an oath by the Temple, it is nothing; but whoever takes an oath by the gold of the Temple, he is responsible.

Because

Matthew 6:27
And which of you by taking thought is able to make himself a cubit taller?
Luke 12:25
And which of you by taking thought is able to make himself any taller?

General references

Luke 12:25
And which of you by taking thought is able to make himself any taller?

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain