Matthew 5:33-37 (NLT)
33"Again, you have heard that it was said to the people long ago, 'Do not break your oath, but keep the oaths you have made to the Lord.' 34But I tell you, Do not swear at all: either by heaven, for it is God's throne; 35or by the earth, for it is his footstool; or by Jerusalem, for it is the city of the Great King. 36And do not swear by your head, for you cannot make even one hair white or black. 37Simply let your 'Yes' be 'Yes,' and your 'No,' 'No'; anything beyond this comes from the evil one.

These verses are a part of the Sermon on the Mount that Jesus gave to all the people gathered there. Jesus was validating the law in that He had not come to abolish the law, but that He might fulfill the law. The law was something, which should be taught and practiced. Jesus reminded the people to keep their promises that were made to God. He went on to say a person should not swear by God or the creations of God. Instead the person should give a response that is straight forward.

God is holy because of who He is, not what He does. Jesus said He came not to abolish the law; instead he lived it for others to witness and follow. The law was no longer words to point out righteousness, but was righteousness in the flesh of Jesus Christ. His life pointed back to a perfect and holy God. Men had corrupted their practices of the law using God’s name and creation as their witness. They were likely to take an oath and then break their promise. Jesus wanted everyone to consider what true righteousness meant. It is deep, real, more solid than imagined and takes in every aspect of our life, including our words and thoughts. But only Jesus could fulfill the law and His righteousness far exceeded anything the Pharisees or Scribes could even dream of. The sermon Jesus gave was not to weight down and condemn us; but it was to give us hope that God’s intent is for us to become righteous and holy in His sight. God wants us to have a holy life so He gave His son Jesus to share with us His true righteousness. Praise God Jesus came to fulfill the law and though faith in Him lives in our lives that we might be seen holy and pure.