'Swear' in the Bible
"Again, you have heard that it was said to the ancients, 'Thou shalt not swear falsely, but shalt perform thy vows to the Lord.'
But I tell you not to swear at all; neither by Heaven, for it is God's throne;
And do not swear by your head, for you cannot make one hair white or black.
And to whom did He swear that they should not be admitted to His rest, if it was not to those who were disobedient?
For when God gave the promise to Abraham, since He had no one greater to swear by, He swore by Himself,
For men swear by what is greater than themselves; and with them an oath in confirmation of a statement always puts an end to a dispute.
But above all things, my brethren, do not swear, either by Heaven or by the earth, or with any other oath. Let your 'yes' be simply 'yes,' and your 'no' be simply 'no;' that you may not come under condemnation.