Behold, I send you out as sheep in the midst of wolves; so be wise as serpents and innocent as doves. Beware of men; for they will deliver you up to councils, and flog you in their synagogues, and you will be dragged before governors and kings for my sake, to bear testimony before them and the Gentiles. When they deliver you up, do not be anxious how you are to speak or what you are to say; for what you are to say will be given to you in that hour; for it is not you who speak, but the Spirit of your Father speaking through you. Mat 10:16-20
What exactly do you do when you suspect someone is being false with you? What do you do when someone stoops to calling you names or slanders you? For that matter, what if you are being falsely accused of something? These are not theoretical considerations. I suspect there are any number of people for whom they are very real circumstances.
The question is an all encompassing one. How are we to conduct ourselves in the world? Should we adopt the mores and standards of the society around us or are we expected to do something different... to be something different. To what extent should we rely on the courts, tribunals and legislatures of this world for truth and justice? Much of this is beyond the scope of this simple blog so let us keep to one simple question. What do you do if you catch someone in a lie?
In the excerpt from Matthew, Jesus is telling his disciples to be both wise and innocent. Other translations use the words cunning and harmless or simple. The contrast between the two is particularly telling. A snake is quite cunning in perceiving and avoiding danger but it can be quite dangerous itself. If you step on a snake you may be bitten. A dove is another story. Anyone who has observed flocks of pigeons knows that they are harmless but they can be incredibly dumb. In combining these two images, Jesus is telling his disciples that he wants them to be wise in the ways of the world and aware of the evil around them. However he does not want his disciples to return evil in kind. Indeed, he counsels them to offer no resistance to the wicked. This is far more than is usually imagined for in order to turn the other cheek you must at least stand your ground.
What do you do if someone lies to you in order to get something? The answer is simple... give it to him if it does no harm... and then point out that the lie was not necessary. In doing so you may gain a brother.
No, "if your enemy is hungry, feed him; if he is thirsty, give him drink, for by so doing you will heap burning coals upon his head." Rom 12:20