1. God's Word has much to say regarding speech, understood here as "active verbal communication," as opposed to listening, which we would define as "passive verbal communication." Material for excellent sermons is contained in any of the following passages.
2. In our text passage today, however, Jesus zeroes in on one particular and unique speech "accessory:" the o __ __ __. Our speech culture of the 20th century western world does not involve itself much with the oath -- it was much more prevalent in Bible times. But we do sometimes become involved with v __ __ __ and pepper our communications with p __ __ __ __ __ __ __. Let us consider all three this morning in the light of our Lord's teaching on the Galilean mountainside.
"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' by 'Yes,' and your 'No,' 'No.' For whatever is more than these is from the evil one."
1. For the first time in this passage Jesus does not quote directly from the Decalogue. This should serve to remind us yet again that Jesus in Matthew 5:17-48 (quickview)  does not take issue with the Mosaic law; His contention was with the centuries of scribal, rabbinical and Pharisaic tampering which had added layers of man-made doctrines and traditions to the 10 Commandments which God had delivered to His people at Sinai. As we have said, Jesus began His discourse on the law by declaring that He had not come to abolish the law, but to fulfill the law -- to "fill it full of meaning." That process, we have seen, often required that Jesus deal first with the popular "understanding" of the specific laws about which He taught and which had been tainted or slanted by generations of "creative" religious teaching.
2. What Jesus is addressing here is, of course, the 3rd Commandment.
You shall not take the name of the Lord your God in vain, for the Lord will not hold him guiltless who takes His name in vain.
And you shall not swear by My name falsely, nor shall you profane the name of your God: I am the Lord.