Swearing

Colossians3:8

8 But now you must rid yourselves of all such things as these: anger, rage, malice, slander, and filthy language from your lips.

Matthew 5.34-37

34 But I tell you, Do not swear at all: either by heaven, for it is God's throne;

35 or by the earth, for it is his footstool; or by Jerusalem, for it is the city of the Great King.

36 And do not swear by your head, for you cannot make even one hair white or black.

37 Simply let your 'Yes' be 'Yes,' and your 'No,' 'No'; anything beyond this comes from the evil one.