Swearing and oaths are addressed by Jesus in Matthew 5, by James in his epistle, and in Leviticus 19.
In Matthew 5:34-37:
34 But I say unto you, Swear not at all; neither by heaven; for it is God’s throne: 35 Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King. 36 Neither shalt thou swear by thy head, because thou canst not make one hair white or black. 37 But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil.
In James 5:12:
12 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.
In Leviticus 19:12:
12 And ye shall not swear by my name falsely, neither shalt thou profane the name of thy God: I am the LORD.