James 5:12

Above all, my brothers, do not swear an oath, either by heaven or by the earth, or by anything else; let your "Yes" be a plain Yes, and your "No" a plain No, or you will fall under condemnation.

Matthew 5:33-37

"Again, you have heard that the men of old were told, 'You shall not swear falsely, but you must fulfil your oaths to the Lord.'

Matthew 23:16-22

Alas for you, you blind guides, who say, 'If anyone swears by the sanctuary, it does not matter, but if anyone swears by the gold of the sanctuary, it is binding.'

1 Corinthians 11:34

If anyone is hungry, let him eat at home, so that your meetings may not bring down a judgment upon you. The details I will settle when I come.

2 Corinthians 1:17-20

Was it vacillating of me to want to do that? Do I make my plans like a worldly man, ready to say "Yes" and "No" in the same breath?

James 3:1-2

Not many of you should become teachers, my brothers, for you know that we who teach will be judged with greater strictness.

1 Peter 4:8

Above all keep your love for one another strong, because love covers up a host of sins.

3 John 1:2

Dear friend, it is my prayer that everything is going well with you and that you are well; I know it is well with your soul.

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 keep your love for one another strong, because love covers up a host of sins.
3 John 1:2
Dear friend, it is my prayer that everything is going well with you and that you are well; I know it is well with your soul.

Swear not

Matthew 5:33
"Again, you have heard that the men of old were told, 'You shall not swear falsely, but you must fulfil your oaths to the Lord.'
Matthew 23:16
Alas for you, you blind guides, who say, 'If anyone swears by the sanctuary, it does not matter, but if anyone swears by the gold of the sanctuary, it is binding.'

But

2 Corinthians 1:17
Was it vacillating of me to want to do that? Do I make my plans like a worldly man, ready to say "Yes" and "No" in the same breath?

Lest

James 3:1
Not many of you should become teachers, my brothers, 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 your meetings may not bring down a judgment upon you. The details I will settle when I come.