Why Sunday Morning?
For many people, it's just another way of saying Sunday. Certainly, as scholars acknowledge, that's part of what John on Patmos or the writer of the Didache mean in using the phrase. The first day of the week which, in typical Semitic fashion, is also the eighth day of the week. The first and the last.
Two reasons are noted in the ancient church to explain why this day, and not the Jewish Sabbath, became the day of gathering.
First, it is the day of the Resurrection. Second, it is the day when God first spoke light into being in the dramatic first chapter of Genesis. From this they concluded the first/eighth day marked the beginning of a creation, which Christ's resurrection then clearly rooted as the first event in the ending of this world and the reformation of New Heaven and New Earth we associate with the age to come.
Church buildings, which began to appear by the early third century, were often configured so that those entering the building would be facing east. That is, facing the rising sun that would mark a new morning. Christian communities developed the tradition of burying their dead with their feet facing due east. Archaeologist still use this practice to identify when Christianity made inroads into new cities and regions: graves with feet facing east. The image was powerful. When the dead were resurrected and stood up, they would be facing the dawn.
The symbolism is rich and theologically deep. It involves both darkness and light.
In Semitic concepts of time, the next day of the week always began with the sunset, not the dawn. The coming of a new day was, first of all, an extended time of darkness. The new day was met with rest not work; with waiting not doing. Many hours after the day had begun, the eastern horizon would gradually brighten, bringing that remarkable transformation from dark hills to green meadows. Finally, the sun itself would majestically emerge, bathing the world in warmth and the bright light of day.
The coming of the Messiah, along with his death and resurrection, marked the beginning of a new day of creation. The new world has already begun. But, as any Jew would understand, the new day is first a world still shrouded in darkness. It is in this present darkness that the church exists. An outpost of the new day scattered among the dying shadows of the old.
The coming-again of Messiah will be like the coming of the Sunday morning dawn. The bright light of day will finally disperse the shadows of night. The new creation we now embrace in faith will be in front of our very eyes, like the bright light of morning.
And, so it was, that among the ancient believers, the custom arose of that, when parting for a season, one Christians who say to another, "I will see you in the morning."
When their bodies were eventually laid to rest, that was surely in the minds of those who assured the feet were always facing the dawn. Children to parents. Parents to children. "Rest now, sweet one. I will see you in the morning."
They were all waiting for the Day of the Lord.
Each Lord's Day is a renewal of the watchman's eager waiting on the dawn.
The Lord's Day will then be the Day of the Lord.