There are many sayings of Jesus that are difficult to understand, however if we correctly divide the covenants and understand the reason why Jesus said them, they make a lot more sense.
It is important to note that Jesus was born under the law and that the new covenant did not come into effect until after the Holy Spirit came in the upper room. This means that Mathew, Mark, Luke and John were actually part of the old covenant. In fact, Jesus did not speak to any Christians in the gospels because He had not paid for their sins yet.
Jesus was sent to fulfil the law and to bring in the new covenant. But before he could fulfil the law he needed to restore it to it’s perfect holy place. The following scripture shows how Jesus is restoring the old covenant.
… ‘ You shall not murder, and whoever murders will be in danger of the judgment.’ “But I say to you that whoever is angry with his brother without a cause shall be in danger of the judgment. And whoever says to his brother, ‘Raca!’ shall be in danger of the council. But whoever says, ‘You fool!’ shall be in danger of hell fire. Mat 5:21b-22 [NKJV]
The Pharisees had reduced the law to something that could be kept, which was not God’s plan. The law was meant to show us that we are sinners and need a saviour. Jesus is brilliant in his restoration of the law. Look at the following verse.
“You have heard that it was said to those of old, ‘You shall not commit adultery.’ “But I say to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart. Mat 5:27-28 [NKJV]
So once Jesus has restored the law to being impossible He takes it another step.
“If your right eye causes you to sin, pluck it out and cast it from you; for it is more profitable for you that one of your members perish, than for your whole body to be cast into hell. Mat 5:29 [NKJV]
Jesus wanted the listeners to know that their self efforts will not get them to heaven. They were meant to give up and say it is too hard. It is only when we give up that Jesus takes over. It is only by faith in Jesus that anyone is saved, not by law keeping. Jesus captures this extremely well.
“He who loves father or mother more than Me is not worthy of Me. And he who loves son or daughter more than Me is not worthy of Me. Mat 10:37 [NKJV]
This scripture dovetails well into the summary of the old covenant law.
‘And you shall love the LORD your God with all your heart, with all your soul, with all your mind, and with all your strength.’ This is the first commandment. 31 “And the second, like it, is this: ‘You shall love your neighbour as yourself.’ There is no other commandment greater than these.” Mark 12:30-31
Even though Jesus quoted it he is still quoting the law, it is not part of the new covenant. Jesus wants us to know that getting to heaven by following the law is impossible.
“I do not set aside the grace of God; for if righteousness comes through the law, then Christ died in vain.” Gal 2:21