Again you have heard that God said to our first generation, “Do not swear falsely but deliver your pledges to the Lord;” but I am telling you, do not swear at all, not by heaven for it is God’s throne, nor by the earth for it is his footstool; nor by Jerusalem for it is the Great King’s city,. Do not swear by your head for you can’t make one hair of it white or black. Let your word be simply Yes or No; Anything more than this is from the Evil One.

To back up one’s words by a solemn oath has been a human practice in many times and places. To swear by one’s God has always been considered especially binding. Even today in the UK court witnesses are asked to take an oath upon the Bible, but there is a legal alternative to affirm an intention to tell the truth.

Jesus rules against this custom because it dishonours God by using his name or some holy thing or place to persuade others; and the swearer is dishonoured by the fact that her simple word is not accepted. Speech, the ability to communicate, is a precious gift of God, and should be used honestly and with care.

Jesus knew what too many demagogues know, that words can respect reality or create fictions which capture people’s allegiance. Plato thought that for this reason artists should be banned from the good state, but it is only necessary to ban lying leaders, while we continue to enjoy our novels and films. Jesus was trying to create a community that respected truth and spoke it wisely. If the inner person is thirled to the facts of God’s world, her speech will be honest.

The serious problem of lying in our societies, using corrupt media like newspapers and television; or social media which take no responsibility for truth, is destructive of social cohesion and of functioning democracy. Jesus’ teaching remains relevant.