"You have also heard that people were told in the past, "Do not break your promise, but do what you have vowed to the Lord to do.' 1
References for Matthew 5:33
But now I tell you: do not use any vow when you make a promise. Do not swear by heaven, for it is God's throne; 2
References for Matthew 5:34
nor by earth, for it is the resting place for his feet; nor by Jerusalem, for it is the city of the great King. 3
References for Matthew 5:35
Do not even swear by your head, because you cannot make a single hair white or black.
Just say "Yes' or "No' - anything else you say comes from the Evil One.