These remained faithful to the teaching of the apostles, to the brotherhood, to the breaking of bread and to the prayers.
Luke offers a really simple ecclesiology: faithful to the teachings of the apostles, faithful to the brotherhood, faithful to breaking bread, and faithful to the prayers. Teaching. Community. Eucharist. Prayer.
And it is the teaching of the apostles. Following Jesus is no longer the issue but not its following the apostles. This is a discipling community.
And again past tense. Luke has the advantage of hindsight. What shipwrecked the early church? An end to discipleship. Disputes which broke the fellowship. Bread was no longer broken with one another. Factions divided the prayers.