Yes God does write His laws on our hearts,but again THE APOSTLES NEVER mentioned it to the Gentile Churches in their writings. The Gentiles were never given the law. They never had the SABBATH teachings so why did the Apostles leave out teaching on the Sabbath to the Gentile churches? The apostles write on EVERY OTHER COMMANDMENT including Jesus commandments to the Gentile churches but not ONCE on the Sabbath other then to not let others judge one about Sabbath days? It's just not there and you can't find where they ever did write to the gentile churches about it.
Act 13:42 And when the Jews were gone out of the synagogue,
the Gentiles besought that these words might be preached to them
the next sabbath.
Act 13:44 And
the next sabbath day came almost
the whole city together to hear the word of God.
And what city was this in?
Act 13:14 But when they departed from Perga, they came to
Antioch in Pisidia, and went into the synagogue on the sabbath day, and sat down.
A Gentile city and these were Gentiles.
Another example...
Act 16:12 And from thence to
Philippi, which is the chief city of that part of Macedonia, and a colony: and we were in that city abiding certain days.
Another Gentile city.
Act 16:13 And on the
sabbath we went out of the city by a river side, where prayer was wont to be made; and we sat down, and spake unto the women which resorted thither.
Now I know you would like to this to say that on the first day of the week they went down to the river adn spoke to the women there, but it just doesn't.
Act 16:14 And a certain woman named Lydia, a seller of purple, of the
city of Thyatira, which worshipped God, heard us: whose heart the Lord opened, that she attended unto the things which were spoken of Paul.
Act 16:15 And when she was baptized, and her household, she besought us, saying, If ye have judged me to be faithful to the Lord, come into my house, and abide there. And she constrained us.
Here is a Gentile convert baptized by Paul's speaking on the Sabbath.
How about Thessalonica?
Act 17:1 Now when they had passed through Amphipolis and Apollonia, they came to
Thessalonica, where was a synagogue of the Jews:
Act 17:2 And Paul, as his manner was, went in unto them, and
three sabbath days reasoned with them out of the scriptures,
Act 17:3 Opening and alleging, that Christ must needs have suffered, and risen again from the dead; and that this Jesus, whom I preach unto you, is Christ.
Act 17:4 And some of them believed, and consorted with Paul and Silas; and of the
devout Greeks a great multitude, and of the chief women not a few.
Interesting thing here, the Gentiles believed from Paul's reasoning with them on the Sabbath. Guess who didn't believe...
Act 17:5 But the
Jews which believed not, moved with envy, took unto them certain lewd fellows of the baser sort, and gathered a company, and set all the city on an uproar, and assaulted the house of Jason, and sought to bring them out to the people.
So, another case of Gentiles being converted by speaking and teaching on the Sabbath.
Now, let me ask two questions.
1) Where did you get this information...
"The Gentiles were never given the law. They never had the SABBATH teachings so why did the Apostles leave out teaching on the Sabbath to the Gentile churches?"
2) Can you show me where they actually kept the first day of the week?