Justin Martyr worship described house church gatherings in the Early Church. "On the day called Sunday, there is a meeting for all in one place, according to the city or town where one lives. The "Memoirs of the Apostles" (the Gospels), or the "Writings of the Prophets", are read as long as there is time. When the reader has finished, the President, in a sermon, calls us all to imitate these good things. Then we all stand and pray."
Justin Martyr described the leader of worship as "president" because non-Christians might not have understood special words such as "bishop" or "presbyter." John Foster in "The First Advance - Church History 1: AD 29-500" wrote, "The three items mentioned, reading of Scripture, a sermon based on the reading, and prayers (which were said standing), followed the custom of the synagogue. Justin Martyr described the New Testament lesson as being from the Gospels (and placed this first), and the Old Testament lesson as an alternative, from the Prophets." For further light on Early Church worship see also Justin Martyr's Interview.