All you need. Nothing you don't.
Here are a few keen lines from a couple of guys who seemed to have “gotten it.” One author is quoting another. I realize this short quotation leaves unanswered questions for many. In years past, I myself would have attempted to deconstruct it and discard it.
The phrase ‘the church in your house’ means just that: the one, spiritual, church is present, as Christ is present, whole and entire, in that person’s house. Strictly speaking the local church, considered as a human society, does not exist. It has no place in the economy of God. The idea of the local church, especially a defined congregation in today’s sense of the word, simply does not exist so far as the organization of the Church is concerned.”
Such a church knows nothing of legal organization. Christ is the Head of the church and his authority is recognized in the exercise of gifts of the Spirit. Everything rests on these charismata, which are the direct gift of Christ to his church, manifest from time to time in different people. ‘There can be no legal constitution and no official body with legislative power in the Ecclesia.’* This is not to say that the church is without order. Quite the opposite! But it is not a legal order, but a charismatic order.
*Rudolf Sohm, from Kirchenrecht. Quoted by Alastair Campbell.
In other words, there is no “core group” to assemble with the hope of organizing, no local church to “plant” and no vacant church offices to be filled in order to “constitute a true church.” Every believer, rather, is expected to use his or her gifts for the good of others as they simply meet as the church.
The evangelization of persons rather than the organization of churches was the passion of the first Christians. We tend to get is backwards.
Furthermore, to view of the early church apart from the household matrix is to view it amiss.