The High Watermark Jesus Set

In Mosaic Law retaliation is limited to, for example, an eye for an eye.  There are 613 commandments in all.  These laws were all about saying "at the lest; do this.."
But Jesus did the opposite; Jesus said in effect do the most possible.  He wasn't interested in telling people where the bare minimum watermark was.  He told them what the best of possibilities were, and we can all achieve these high watermarks of righteousness.
"But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment: and whosoever shall say to his brother, Raca, shall be in danger of the council: but whosoever shall say, Thou fool, shall be in danger of hell fire.
²³ Therefore if thou bring thy gift to the altar, and there rememberest that thy brother hath ought against thee;
²⁴ Leave there thy gift before the altar, and go thy way; first be reconciled to thy brother, and then come and offer thy gift."  (Matthew 5:22-24)
Jesus is saying that the bare minimum is to not kill, but the high watermark is to not even be angry. He asks us to reach the high water mark of not even being angry toward or hold a grudge against anyone.  Jesus is saying His high watermark is now the new bare minimum.  Hate or anger is on par with killing in Jesus' mind.
 "Ye have heard that it was said by them of old time, Thou shalt not commit adultery:
 But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart." (Matthew 5:27-28)
"Thou shalt not covet thy neighbour's house, thou shalt not covet thy neighbour's wife, nor his manservant, nor his maidservant, nor his ox, nor his ass, nor any thing that is thy neighbour's." (Exodus 20:17)
If you have lust in your heart I'm sure that counts as coveting.  Jesus is comparing lust for anyone who is not your spouse to adultry.  He also compares hate to murder.  Jesus is asking for much more than the bare minimums of Mosaic Law.
 "Then came Peter to him, and said, Lord, how oft shall my brother sin against me, and I forgive him? till seven times?
Jesus saith unto him, I say not unto thee, Until seven times: but, Until seventy times seven."(Matthew 18:21-22)
"If Cain shall be avenged sevenfold, truly Lamech seventy and sevenfold." (Genesis 4:24)
This reference to 70 times 7 or 77 is symbolic of infinity some may roll their eyes at the thought of Jews being obsessed with numerology but they did have a form of it called Gematria.  Jesus is saying we should meet hate with unlimited and unconditional love.  We should place no limits as God places no limits on His forgiveness of us.  We can repay The Lord's kindness by being as forgiving toward others as He is toward us.  We can take part in the Atonement by paying that love and forgiveness forward.
Lamech is considered to be one of the most wicked and vengeful characters in scripture so Jesus by saying that we should be as forgiving and loving as Lamech is vengful and hateful.
Why be less than your best?
 "And if any man will sue thee at the law, and take away thy coat, let him have thy cloak also.
And whosoever shall compel thee to go a mile, go with him twain." (Matthew 5:40-41)
Coat in this case means tunic or shirt but cloak means coat and it's what most used to sleep with or for collateral so the cloak is much more valuable yet Jesus is saying if someone takes your less valuable shirt give them your highly valuable coat.  It's like saying if someone takes yur mountain bike give them you SUV as well.
And being "compelled" is also translated accurately as "forced."  Roman soldiers often conscripted Jews to carry their equipment.  Thus was a regular occurrence in Christ's time.  And rather than telling the soldier off and running away Jesus says we should go twice as far or go the extra mile so to speak.
"Ye have heard that it hath been said, Thou shalt love thy neighbour, and hate thine enemy.
⁴⁴ But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you;
⁴⁵ That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust.
⁴⁶ For if ye love them which love you, what reward have ye? do not even the publicans the same?
⁴⁷ And if ye salute your brethren only, what do ye more than others? do not even the publicans so?
⁴⁸ Be ye therefore perfect, even as your Father which is in heaven is perfect." (Matthew 5:43-48)
Now this may not always work as well as you may hope; every one still has the free agency to react and respond however they choose.  But it is possible to destroy your enemies when you make them your friends as Lincoln claimed to.
Hate cannot drive out hate, only love can do that.  Darkness cannot drive out darkness, only light can do that. -Dr. Martin Luther King
Jesus takes what sounded normal to His audience and makes all too much sense in our own time which is "Love thy neighbor and hate thine enemy."  And He turns our world upside down when He says we are to Love or enemies, do good to them that hate you.
He asks what reward is there in playing life as a this for that game.  If you do good to me I reciprocate, if you do bad to me I reciprocate.  Jesus is saying we should unconditionally respond with limitless love regardless of how we are treated.  He is saying that there is great reward in softening a hardened heart.
"A new commandment I give unto you, That ye love one another; as I have loved you, that ye also love one another.
³⁵ By this shall all men know that ye are my disciples, if ye have love one to another." (John 13:30-35)
To walk the path Christ has is what it takes to truly be a disciple it has nothing to do with the creeds and doctrines of men and institutions of more men.  All men will know we are Christ's disciples if we have love like His one to another.