What is for us the meaning of Jesus' words in Mat.5 :17-20?
17 "You should not infer that I came to demolish the law or the prophets. I came not to demolish, but to fulfill.
18 For verily, I am saying to you, Till heaven and earth should be passing by, one iota or one serif may by no means be passing by from the law till all should be occurring.
19 "Whosoever, then, should be annulling one of the least of these precepts, and should be teaching men thus, the least in the kingdom of the heavens shall he be called. Yet whoever should be doing and teaching them, he shall be called great in the kingdom of the heavens.
20 For I am saying to you that, if ever your righteousness should not be superabounding more than that of the scribes and Pharisees, by no means may you be entering into the kingdom of the heavens.
First, we need to remember that Jesus, according to His own words, was ONLY sent to the house of Israel. And He added that it is NOT GOOD to give the bread of the children of Israel to the nations. (Matt.15:24-26). This also applies to these words in the "sermon on the mount". However much we can learn of these words, we should be aware that they are not addressed to us.
According to the apostle Paul (who is the "teacher of the nations"; 1Tim.2:7), Jesus was born under the law (Gal.4:4). Why? In order to redeem those (=to FREE those), who were under the law (Gal.4:4,5). The law, which was given on Mount Horeb to Israel, 430 years after God's promise to Abraham (Gal.3: 17), has been an escort TO CHRIST (Gal.3:24). Please note: It does not say "to Jesus", because that would not be correct. No, "to Christ", a title that refers to His resurrection from among the dead (Acts 2:36). In this path of obedience unto death, Jesus Christ FULFILLED the law, even as He also fulfills the prophecies, in the past, the present and in the future.
The law also is prophecy!
The righteousness that is ours, as believers in Christ, we have not acquired, but have RECEIVED. And abundantly so!
For if, by the offense of the one,
death reigns through the one,
much rather, those OBTAINING
the SUPERABUNDANCE of grace
and the gratuity of righteousness
shall be reigning in life
through the One, Jesus Christ.
Translation: Peter Feddema