Matthew 5.39 reads like this:

“But I say vnto you, ^*that yee resist not euill: but whosoeuer shall smite thee on thy right cheeke, turne to him the other also.”

In German:

“Aber ich sage euch, ^*dass ihr Bösem nicht widersteht: Sondern wer auch immer euch auf die rechte Wange schlägt, wendet ihm die andere auch hin.“

This part of the sermon on the mount lead to numerous misunderstandings of what Christians are and how they (should) behave and what that means to non-Christians.

Jesus tells us, that we “don’t resist evil”. But he doesn’t want to insult us or tell us we don’t, even we should. Not at all. He is telling us, that we can’t fight back evil - and therefore we should not - and more: we don’t need to. If we engage ourselves into a fight against evil, we will be consumed.- The evil is much more powerful than we human beings, because it is spiritual. If we fight back with earthly power and muscles, we loose. So, instead of fighting back evil that strikes our right cheek, we do something that disarms any enemy: We offer him the other cheek.

But is that a sign of weakness? No. The opposite is true. If you hit an enemy as hard as you can and instead of trying to hit you back the same way, you offer him another hit against you, shows this enemy how weak he really is. His hit doesn’t impress or hurt you. You invite him to try again. And if your enemy, evil, is clever, it will think twice to follow this “invitation”.

A good boxer knows this trick very well. And the impatient opponent will take the invitation, try to set even a second hit, but you know his plan already and his second hit will fail, giving you the opportunity to hit him back even harder and knock him out.

A clever enemy knows about that and will not even try to set a second hit, but is aware of your cleverness. Some people you deal with in that way will be totally shocked and stunned. And you now know why.

Real life experience confirms this unintuitive lesson over and over again. The devil hates people that know about this.

This applies to Matthew 5:40 as well: Offering an accuser before court not only what he demands, but even more, shows your enemy your superiority above him and he will be careful to do any further move against you.