Matthew 5:33-37

Jesus said to the crowds, “Again, you have heard that it was said to those of ancient times, ‘You shall not swear falsely, but carry out the vows you have made to the Lord.’ But I say to you, Do not swear at all, either by heaven, for it is the throne of God, or by the earth, for it is his footstool, or by Jerusalem, for it is the city of the great King. And do not swear by your head, for you cannot make one hair white or black. Let your word be ‘Yes, Yes’ or ‘No, No’; anything more than this comes from the evil one.”

To speak the truth in God and only in God is the concern of Jesus here. In prayer and in reflection, in conversation with others, the life and truth of God deepen in each of us. Our ‘yes’ to life and in life is the ‘yes’ of God. Nothing is worth our commitment in life but the truth of God and the meaning in life that is given to us by Jesus Christ.

Further commentary available here