Matthew 5:36

"Nor must you swear by your head, since you cannot make one hair white or black.

Matthew 6:27

"Which one of you by being anxious is able to add even one cubit to his stature?

Matthew 23:16-21

"Woe unto you, blind guides, who say, If any one swears by the Sanctuary, it is nothing, but if any one swears by the gold of the Sanctuary, the oath is binding.

Luke 12:25

"And which of you by taking anxious thought can add a cubit to his height?

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, blind guides, who say, If any one swears by the Sanctuary, it is nothing, but if any one swears by the gold of the Sanctuary, the oath is binding.

Because

Matthew 6:27
"Which one of you by being anxious is able to add even one cubit to his stature?
Luke 12:25
"And which of you by taking anxious thought can add a cubit to his height?

General references

Luke 12:25
"And which of you by taking anxious thought can add a cubit to his height?