James 5:12

Now above all, my brothers, do not swear either by heaven or by earth or by any other oath, but let your yes be yes and your no, no, in order that you may not fall under judgment.

Matthew 5:33-37

"Again you have heard that it was said to the {people of old}, 'Do not swear falsely, but fulfill your oaths to the Lord.'

Matthew 23:16-22

"Woe to you, blind guides, who say, 'Whoever swears by the temple, it is nothing! But whoever swears by the gold of the temple is bound [by his oath].'

1 Corinthians 11:34

If anyone is hungry, let him eat at home, lest you come together for judgment. And I will give directions about the remaining [matters] whenever I come.

2 Corinthians 1:17-20

Therefore, [when I] was wanting [to do] this, perhaps then was I making use of vacillation? Or was I deciding what I was deciding according to the flesh, in order that with me my "yes" may be "yes" and my "no" [may be] "no" [at the same time]?

James 3:1-2

Not many should become teachers, my brothers, [because you] know that we will receive a greater judgment.

1 Peter 4:8

Above all, keep your love for one another constant, because love covers a large number of sins.

3 John 1:2

Dear friend, I pray you may prosper concerning everything and be healthy, just as your soul prospers.

Treasury of Scripture Knowledge

Summary

But above all things, my brethren, swear not, neither by heaven, neither by the earth, neither by any other oath: but let your yea be yea; and your nay, nay; lest ye fall into condemnation.

General references

Bible References

Above

1 Peter 4:8
Above all, keep your love for one another constant, because love covers a large number of sins.
3 John 1:2
Dear friend, I pray you may prosper concerning everything and be healthy, just as your soul prospers.

Swear not

Matthew 5:33
"Again you have heard that it was said to the {people of old}, 'Do not swear falsely, but fulfill your oaths to the Lord.'
Matthew 23:16
"Woe to you, blind guides, who say, 'Whoever swears by the temple, it is nothing! But whoever swears by the gold of the temple is bound [by his oath].'

But

2 Corinthians 1:17
Therefore, [when I] was wanting [to do] this, perhaps then was I making use of vacillation? Or was I deciding what I was deciding according to the flesh, in order that with me my "yes" may be "yes" and my "no" [may be] "no" [at the same time]?

Lest

James 3:1
Not many should become teachers, my brothers, [because you] know that we will receive a greater judgment.
1 Corinthians 11:34
If anyone is hungry, let him eat at home, lest you come together for judgment. And I will give directions about the remaining [matters] whenever I come.

General references

Deuteronomy 5:11
You shall not take up the name of Yahweh your God for worthless purpose, for Yahweh will not leave unpunished [anyone] who uses his name for worthless purpose.