In Solomon: “A man that sweareth much shall be filled with iniquity, and the plague shall not depart from his house; and if he swear vainly, he shall not be justified.” Of this same matter, according to Matthew: “(Again, ye have heard that it was said to them of old, Thou shalt not swear falsely, but shalt perform unto the Lord thine oaths.) I say unto you, Swear not at all: (neither by heaven, because it is God’s throne; nor by the earth, because it is His footstool; nor by Jerusalem, because it is the city of the great King; neither shalt thou swear by thy head, because thou canst not make one hair white or black.) But let your discourse be, Yea, yea; Nay, nay: (for whatever is fuller than these is of evil.”) Of this same thing in Exodus: “Thou shalt not take the name of the Lord thy God in vain.”
Reproduced in full. Translation: Ante-Nicene Fathers, vol. 5 (Roberts and Donaldson, 1886), public domain (Public domain).