Matthew 5:36

Nor, by thine own head, mayest thou swear, because thou art not able to make, one hair, white or black.

Matthew 6:27

But who from among you, being anxious, can add to his stature one cubit?

Matthew 23:16-21

Alas for you, blind guides! that say - Whosoever shall swear by the Temple, it is, nothing, but, whosoever shall swear by the gold of the Temple, is bound:

Luke 12:25

And, who from among you, though anxious, can, unto his stature, add a cubit?

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, blind guides! that say - Whosoever shall swear by the Temple, it is, nothing, but, whosoever shall swear by the gold of the Temple, is bound:

Because

Matthew 6:27
But who from among you, being anxious, can add to his stature one cubit?
Luke 12:25
And, who from among you, though anxious, can, unto his stature, add a cubit?

General references

Luke 12:25
And, who from among you, though anxious, can, unto his stature, add a cubit?