James 5:12

But above all things, my brethren, swear not, either by heaven, or by the earth, or with any other oath: but let your yes, be yes, and your no, be no, lest you fall into condemnation.

Matthew 5:33-34

Again, you have heard that it was said to the ancients: You shall not swear falsely, but shall pay to the Lord your vows.

Treasury of Scripture Knowledge

Summary

And ye shall not swear by my name falsely, neither shalt thou profane the name of thy God: I am the LORD.

Bible References

Ye shall

Matthew 5:33
Again, you have heard that it was said to the ancients: You shall not swear falsely, but shall pay to the Lord your vows.
James 5:12
But above all things, my brethren, swear not, either by heaven, or by the earth, or with any other oath: but let your yes, be yes, and your no, be no, lest you fall into condemnation.