Matthew 5:36

Nor shall you make an oath by your head, for you are not able to make a single hair white or black.

Matthew 6:27

And who of you by worrying can add one hour to [the length of] his life?

Matthew 23:16-21

“Woe to you, blind guides, who say, ‘Whoever swears [an oath] by the sanctuary of the temple, that is nothing (non-binding); but whoever swears [an oath] by the gold of the temple is obligated [as a debtor to fulfill his vow and keep his promise].’

Luke 12:25

And which of you by worrying can add one hour to his life’s span?

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 to you, blind guides, who say, ‘Whoever swears [an oath] by the sanctuary of the temple, that is nothing (non-binding); but whoever swears [an oath] by the gold of the temple is obligated [as a debtor to fulfill his vow and keep his promise].’

Because

Matthew 6:27
And who of you by worrying can add one hour to [the length of] his life?
Luke 12:25
And which of you by worrying can add one hour to his life’s span?

General references

Luke 12:25
And which of you by worrying can add one hour to his life’s span?