***Did you or someone else just make up this meeting on Sunday practice, or are you commanded to by Scripture ? ***
No sweat!
The day Christ rose.
Matthew 28:1
In the end of the sabbath, as it began to dawn toward the first day of the week, came Mary Magdalene and the other Mary to see the sepulchre.
Mark 16:2
And very early in the morning the first day of the week, they came unto the sepulchre at the rising of the sun.
Mark 16:9
Now when Jesus was risen early the first day of the week, he appeared first to Mary Magdalene, out of whom he had cast seven devils.
Luke 24:1
Now upon the first day of the week, very early in the morning, they came unto the sepulchre, bringing the spices which they had prepared, and certain others with them.
John 20:1
The first day of the week cometh Mary Magdalene early, when it was yet dark, unto the sepulchre, and seeth the stone taken away from the sepulchre.
***John 20:19***
Then the same day at evening, being the first day of the week, when the doors were shut where the disciples were assembled for fear of the Jews, came Jesus and stood in the midst, and saith unto them, Peace be unto you.
Now pay special attention to these two verses.
***Acts 20:7***
And upon the first day of the week, when the disciples came together to break bread, Paul preached unto them, ready to depart on the morrow; and continued his speech until midnight.
***1 Corinthians 16:2***
Upon the first day of the week let every one of you lay by him in store, as God hath prospered him, that there be no gatherings when I come.