Brother he was talking about both. Fulfilling or the prophetic scriptures and showing the true meaning and application of God's 10 Commandments as Jesus uses the example of thou shalt not kill and thou shalt not commit adultery.
MATTHEW 5:17-29
[17], Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfill.
[18], For truly I say to you,
Till heaven and earth pass, one stroke or one pronunciation mark
shall in no wise pass from the law, till all be fulfilled.
[19],
Whoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whoever shall do and teach them, the same shall be called great in the kingdom of heaven.
[20], For I say to you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, you shall in no case enter into the kingdom of heaven.
[21], You have heard that it was said of them of old time,
You shall not kill; and whoever shall kill shall be in danger of the judgment:
[22], But I say to you,
That whoever is angry with his brother without a cause shall be in danger of the judgment: and whoever shall say to his brother, Raca, shall be in danger of the council: but whoever shall say, You fool, shall be in danger of hell fire.
[23], Therefore if you bring your gift to the altar, and there remember that your brother has ought against you;
[24], Leave there your gift before the altar, and go your way; first be reconciled to your brother, and then come and offer your gift.
[25], Agree with your adversary quickly, whiles you are in the way with him; lest at any time the adversary deliver you to the judge, and the judge deliver you to the officer, and you be cast into prison.
[26], Truly I say to you, You shall by no means come out there, till you have paid the uttermost farthing.
[27], You have heard that it was said by them of old time,
You shall not commit adultery:
[28], But
I say to you, That whoever looks on a woman to lust after her has committed adultery with her already in his heart.
[29], And if your right eye offend you, pluck it out, and cast it from you: for it is profitable for you that one of your members should perish, and not that your whole body should be cast into hell.
Yep Jesus is certainly referencing the 10 Commandment applying them to the thoughts and feelings. Seems like we need a new heart because ours is broken.
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NOTE: After stating that none of God's LAW (10 Commandments) have been abolished
v17-19, Jesus then goes on to say;
v20 For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, you shall in no case enter into the kingdom of heaven.
Jesus then goes on and amplifies the application of God's LAW to the heart (thoughts and feelings) which is the very root of sin saying that if we lust after women we are committing Adultery and being angry with your brother as murder from the 10 commandments as examples in
v17-27.Jesus starts out by saying;
Jesus finishes by saying in
v48 Be ye therefore perfect, even as your Father which is in heaven is perfect.
Looks like we have a broken heart that has no LOVE that needs fixing and we are all sinners in need of a Saviour.
May God bless you as you seek him through his Word.