The Law and the Prophets
Just for a bit of background, here is a short blurb from The Catholic Study Bible, Reading Guide, Page 4, about the Law and the Prophets as currently understood by Bible scholars.
Words of Jesus about Law, Prophets, and Greatness
Matthew 5:17-19 “Do not think that I have come to abolish the law or the prophets. I have come not to abolish but to fulfill. Amen, I say to you, until heaven and earth pass away, not the smallest letter or the smallest part of a letter will pass from the law, until all things have taken place. Therefore, whoever breaks one of the least of these commandments and teaches others to do so will be called least in the kingdom of heaven. But whoever obeys and teaches these commandments will be called greatest in the kingdom of heaven.
Matthew 18:1-4 At that time the disciples approached Jesus and said, “Who is the greatest in the kingdom of heaven?” He called a child over, placed it in their midst, and said, “Amen, I say to you, unless you turn and become like children, you will not enter the kingdom of heaven. Whoever humbles himself like this child is the greatest in the kingdom of heaven.
Matthew 22:36-40 “Teacher, which commandment in the law is the greatest?” 37 He said to him, “You shall love the Lord, your God, with all your heart, with all your soul, and with all your mind. 38 This is the greatest and the first commandment. 39 The second is like it: You shall love your neighbor as yourself. 40 The whole law and the prophets depend on these two commandments.”
Disciples Argue About Greatness Twice in Luke and Get Schooled
Luke 9:46-48 An argument arose among the disciples about which of them was the greatest. Jesus realized the intention of their hearts and took a child and placed it by his side and said to them, “Whoever receives this child in my name receives me, and whoever receives me receives the one who sent me. For the one who is least among all of you is the one who is the greatest.”
Luke 22:24-26 Then an argument broke out among them about which of them should be regarded as the greatest. He said to them, “The kings of the Gentiles lord it over them and those in authority over them are addressed as ‘Benefactors’; but among you it shall not be so. Rather, let the greatest among you be as the youngest, and the leader as the servant.
Jesus on Deeper Meanings of Some Commandments (Law)
Matthew 5:21-48 “You have heard that it was said to your ancestors, ‘You shall not kill; and whoever kills will be liable to judgment.’ But I say to you, whoever is angry with his brother will be liable to judgment, and whoever says to his brother, ‘Raqa,’ will be answerable to the Sanhedrin, and whoever says, ‘You fool,’ will be liable to fiery Gehenna. Therefore, if you bring your gift to the altar, and there recall that your brother has anything against you, leave your gift there at the altar, go first and be reconciled with your brother, and then come and offer your gift. Settle with your opponent quickly while on the way to court with him. Otherwise your opponent will hand you over to the judge, and the judge will hand you over to the guard, and you will be thrown into prison. Amen, I say to you, you will not be released until you have paid the last penny.
“You have heard that it was said, ‘You shall not commit adultery.’ But I say to you, everyone who looks at a woman with lust has already committed adultery with her in his heart. If your right eye causes you to sin, tear it out and throw it away. It is better for you to lose one of your members than to have your whole body thrown into Gehenna. And if your right hand causes you to sin, cut it off and throw it away. It is better for you to lose one of your members than to have your whole body go into Gehenna.
“It was also said, ‘Whoever divorces his wife must give her a bill of divorce.’ But I say to you, whoever divorces his wife (unless the marriage is unlawful) causes her to commit adultery, and whoever marries a divorced woman commits adultery.
“Again you have heard that it was said to your ancestors, ‘Do not take a false oath, but make good to the Lord all that you vow.’ But I say to 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 city of the great King. Do not swear by your head, for you cannot make a single hair white or black. Let your ‘Yes’ mean ‘Yes,’ and your ‘No’ mean ‘No.’ Anything more is from the evil one.
“You have heard that it was said, ‘An eye for an eye and a tooth for a tooth.’ But I say to you, offer no resistance to one who is evil. When someone strikes you on (your) right cheek, turn the other one to him as well. If anyone wants to go to law with you over your tunic, hand him your cloak as well. Should anyone press you into service for one mile, go with him for two miles. Give to the one who asks of you, and do not turn your back on one who wants to borrow.
“You have heard that it was said, ‘You shall love your neighbor and hate your enemy.’ But I say to you, love your enemies, and pray for those who persecute you, that you may be children of your heavenly Father, for he makes his sun rise on the bad and the good, and causes rain to fall on the just and the unjust. For if you love those who love you, what recompense will you have? Do not the tax collectors do the same? And if you greet your brothers only, what is unusual about that? Do not the pagans do the same?
So be perfect, just as your heavenly Father is perfect.
But, No Command in OT to Hate Enemies
Proverbs 25:21-22 If your enemy be hungry, give him food to eat, if he be thirsty, give him to drink; For live coals you will heap on his head, and the LORD will vindicate you.
Exodus 23:4-5 “When you come upon your enemy’s ox or ass going astray, see to it that it is returned to him. When you notice the ass of one who hates you lying prostrate under its burden, by no means desert him; help him, rather, to raise it up.
If all the above is not perfectly clear, just chalk it up to Divine Mystery and take comfort in the words of G. K. Chesterton in Orthodoxy, Chapter II, The Maniac: The whole secret of mysticism is this: that man can understand everything by the help of what he does not understand.