Yes, Yes…   And No, No…
 
In ancient times, people did not want to promise something and say, “I swear by God that I will do this.”  Because they felt that if they swore by God, that they were under obligation to keep their oath, and they often wanted to back out of a promise.  So, people used to say things like…
“I swear by heaven”
“I swear by God’s throne”
“I swear by the earth”
“I swear by Jerusalem”
“I swear by my head that I promise to do this or that”
Jesus says that when you give someone your word, you are under obligation to keep it.  If you say, “Yes, I’ll do something,” that you have an obligation not to go back on your word.  If you say, “No, I’m not going to do something,” that you have an obligation not to go back on your word.  It isn’t a matter of what you swear by, it is a matter of speaking the truth.
 
Matthew 5:33-37
Jesus said,  “Again you have heard that it was said to those of old, ‘You shall not swear falsely, but shall perform your oaths to the Lord.’  But I say to you, do not swear at all: neither by heaven, for it is God’s throne; nor by the earth, for it is His footstool; nor by Jerusalem, for it is the city of the great King.  Nor shall you swear by your head, because you cannot make one hair white or black.  But let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No.’  For whatever is more than these is from the evil one.”
 
So how does this verse apply to us in our everyday living?
Well, I have people tell me, “Swear to me that you will do it.”  I often come back and say to them, “I don’t need to swear that I’m going to do it.  I told you that I’m going to do it and that is enough.”  To me, my word should be enough.  I don’t need to make an oath or swear to God that I’m going to keep my promise.