Matthew 16:18, Peter's confession, praying versus preaching

A host reads 'On this rock I will build my church' (Matthew 16:18) and argues Jesus meant Peter's confession of faith, not Peter physically — noting Peter denied Christ to a teenage girl five chapters later. The talk moves to Pentecost: 3,000 came to Christ after the upper-room prayer, and 'Paul says some plant, some water' (1 Corinthians 3:6), so the hosts' calling is prayer, not preaching — 'God's going to raise who he wants to do the speaking.' Chat-room discussion about engagement is addressed: they felt prayer was the assignment, and 'if God had it on us to walk out there,' they would have heard it.