A lot of religions have an oral tradition, but Judaism was one of the first to be written. Ancient scribes were required to copy the Torah word for word, letter for letter, exactly. If they made a mistake, they weren’t allowed to just cross it out and keep going. They had to throw out the entire scroll and start over. That’s how seriously ancient Israelites took the law.
Reading 1
Dt 4:1, 5-9
Moses spoke to the people and said: "Now, Israel, hear the statutes and decrees which I am teaching you to observe, that you may live, and may enter in and take possession of the land which the LORD, the God of your fathers, is giving you. Therefore, I teach you the statutes and decrees as the LORD, my God, has commanded me, that you may observe them in the land you are entering to occupy. Observe them carefully, for thus will you give evidence of your wisdom and intelligence to the nations, who will hear of all these statutes and say, 'This great nation is truly a wise and intelligent people.' For what great nation is there that has gods so close to it as the LORD, our God, is to us whenever we call upon him? Or what great nation has statutes and decrees that are as just as this whole law which I am setting before you today?
"However, take care and be earnestly on your guard not to forget the things which your own eyes have seen, nor let them slip from your memory as long as you live, but teach them to your children and to your children's children."
The Jews are God’s Chosen People. He planned from the beginning to become incarnate from a young Jewish woman, and to preach and teach among the Jews.1
In order for this plan to work, they had to be an example to every nation, with better laws and more closeness to God than anyone else. So God commands them not only to obey, but to pass down the law, through every generation.
Jesus is a part of that tradition. He knew every law, even as a boy, talking with the elders at the temple.
Responsorial Psalm
Ps 147:12-13, 15-16, 19-20
R. Praise the Lord, Jerusalem.
Glorify the LORD, O Jerusalem;
praise your God, O Zion.
For he has strengthened the bars of your gates;
he has blessed your children within you.
R. Praise the Lord, Jerusalem.
He sends forth his command to the earth;
swiftly runs his word!
He spreads snow like wool;
frost he strews like ashes.
R. Praise the Lord, Jerusalem.
He has proclaimed his word to Jacob,
his statutes and his ordinances to Israel.
He has not done thus for any other nation;
his ordinances he has not made known to them.
R. Praise the Lord, Jerusalem.
God can command the elements with just a word. He can make it snow on command, that’s how powerful His word is.
So it’s a big deal that God proclaimed His word to Jacob and give His statutes to Israel. Almost any person can discern the Natural Law, and most civilizations reflect that. But only Israel received laws directly from God himself.
Verse Before the Gospel
See Jn 6:63c, 68c
Your words, Lord, are Spirit and life;
you have the words of everlasting life.
Peter is talking to Jesus here, but since we believe in the Holy Trinity, this applies to all three persons of the Trinity.
Gospel
Mt 5:17-19
Jesus said to his disciples: "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."
Jesus came to Earth as the fulfilment of everything the Old Testament was building up to. “Until heaven and earth pass away” is a colloquialism of the time. It’s another way of saying, “No matter what happens.”
The actual pertinent phrase is “until all things have taken place.” That is, all the prophesies about a Messiah and whatnot. That’s what Jesus is here to do.
After His death and resurrection, we’re in a new age. He has fulfilled the purpose of the Mosaic Law; now, we’re in the age of the Church.
And occasionally some gentiles, but you know what I mean.