James 5:12

But above all things, my brethren, swear not, either by Heaven, or by earth, or by any other oath; but let yours be "the yes, yes," and "the no, no"; that ye fall not under condemnation.

Matthew 5:33-34

"Again ye heard that it was said to the ancients, You shall not swear falsely, but shall perform to the Lord your oaths;"

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 ye heard that it was said to the ancients, You shall not swear falsely, but shall perform to the Lord your oaths;"
James 5:12
But above all things, my brethren, swear not, either by Heaven, or by earth, or by any other oath; but let yours be "the yes, yes," and "the no, no"; that ye fall not under condemnation.