Show me why Sunday is the Day

The NT leaves no doubt that the 10 Commandments are still binding on usRead Mt 5:19. John 14:15,21; 15:10. 1 Cor 7:19. 1 John 2:3-4; 3:22-24; 5:2-3!
2John 6 . Rev 14:2 ; 22:14Hebrews 8 tells about the NT covenant, and why a new one was necessary. note v.8: The fault was with the people, not His laws. V. 10 says God will write
His laws (10 Co) into our heart and mind, not do away with them.Jesus and His apostles kept the 7th day Sabbath. Luke 13:10. Acts 13:,27,
42-44; 15:21; 17:2; 18:4.And so did the Gentile converts: Acts 13: 42-44; 17:2; 18:4. If the Sabbath was no longer in effect why didn't Paul tell these Gentile converts that there was no
Need to wait until the next Sabbath me, he could preach to them the following day--Sunday.

Some quote Romans 14:5-6 to show that the Sabbath is no longer binding. But ,
The Sabbath is nowhere mentioned here. Reference (v 8) is simply "days "The Sabbath (by NT writers) is never referred by the term "one dayThe disputes are about doubtful things--not issues clearly stated in
scripture.Paul is talking about days during which fasting or abstaining from certain food
Was practiced.(Luke 18:12--i fast twice a week.)
Romans 2:17-24. Self-righteous Jews condemned Gentile convertsV. 4. Members were trying to force others to fast on particular days
Fasting is voluntary. Fasting on particular day did not make one more righteous.Paul quotes from the OTore than 80 times in the epistle to the Romans
Paul was not against keeping OT lawsGod's Sabbath is a feast day (Lev 23:1-3), not a day to refrain from meat.