James 5:12

But above all, my brethren, do not swear, either by heaven or by earth or with any other oath, but let your yes be yes and your no be no, that you may not fall under condemnation.

Matthew 5:33-37

"Again you have heard that it was said to those of old, 'You shall not swear falsely, but shall perform your oaths to the Lord.'

Matthew 23:16-22

"Woe to you, blind guides, who say, 'If any one swears by the temple, it is nothing; but if any one swears by the gold of the temple, he is bound by his oath.'

1 Corinthians 11:34

If anyone is hungry, let him eat at home, so that you will not come together for judgment. About the other things I will give directions when I come.

2 Corinthians 1:17-20

When I was planning this, did I do it lightly? Or do I make my plans in a fleshly manner so that in the same breath I say, "Yes, Yes" and "No, No"?

James 3:1-2

Let not many of you become teachers, my brethren, for you know that we who teach will be judged with greater strictness.

1 Peter 4:8

Above all, hold unfailing your love for one another, because love covers a multitude of sins.

3 John 1:2

Beloved, I pray that you may be in good health and that all may go well with you, even as your soul is getting along well.

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.

Bible References

Above

1 Peter 4:8
Above all, hold unfailing your love for one another, because love covers a multitude of sins.
3 John 1:2
Beloved, I pray that you may be in good health and that all may go well with you, even as your soul is getting along well.

Swear not

Matthew 5:33
"Again you have heard that it was said to those of old, 'You shall not swear falsely, but shall perform your oaths to the Lord.'
Matthew 23:16
"Woe to you, blind guides, who say, 'If any one swears by the temple, it is nothing; but if any one swears by the gold of the temple, he is bound by his oath.'

But

2 Corinthians 1:17
When I was planning this, did I do it lightly? Or do I make my plans in a fleshly manner so that in the same breath I say, "Yes, Yes" and "No, No"?

Lest

James 3:1
Let not many of you become teachers, my brethren, for you know that we who teach will be judged with greater strictness.
1 Corinthians 11:34
If anyone is hungry, let him eat at home, so that you will not come together for judgment. About the other things I will give directions when I come.