Jesus’ third example of the unrighteous conduct and scriptural misapplication of the scribes and Pharisees is related to God’s commandment to tell the truth. The scribes and Pharisees had developed a very creative way to lie. We learn from Matthew 23:16-22 that they did not consider themselves obligated to keep their vows if they swore by the temple, the altar, or heaven. However, if they swore by the gold in the temple, the offering on the altar, or by God in heaven, they were obligated to keep their vow! It was an adult equivalent of a child’s thinking he is exempt from having to tell the truth as long as his fingers are crossed behind his back. Jesus expects His disciples to tell the truth.
Again, you have heard that the ancients were told, “You shall not make false vows, but shall fulfill your vows to the Lord.” But I say to you, make no oath at all, either by heaven, for it is the throne of God, or by the earth, for it is the footstool of His feet, or by Jerusalem, for it is the city of the great King. Nor shall you make an oath by your head, for you cannot make one hair white or black. But let your statement be, “Yes, yes” or “No, no”; and anything beyond these is of evil (Matt. 5:33-37).
God’s original commandment concerning vows said nothing about making an oath by swearing on something else. God intended for His people to always speak the truth, so there would be no need to swear, ever.
There is nothing wrong with making an oath. In fact, oaths to obey God are very good. Salvation begins with an oath to follow Jesus. But when people have to swear by something to convince others to believe them, it is an outright admission that they normally lie. People who always tell the truth do not need to swear, ever. Yet the church today is full of liars, and the ministers are often the leaders in deceptiveness and guile.
The disciple-making minister sets an example of truthfulness and teaches his disciples to always tell the truth. He knows John warned that all liars will be cast into the lake that burns with fire and brimstone (see Rev. 21:8).