The church that convinces people that there is a God is a church that manifests what only God can do, that is unite people in Christian love.
There is nothing that convinces people God exists or that awakens cravings for Him like the discovery of Christian brothers and sisters who love one another.
The sight of loving unity in the church arrests the non Christian. It crashes through his intellect, stirs up his conscience and creates a longing in his heart because he was created to enjoy the very thing that the church is demonstrating. John White
Acts 2:44-47
John 13:34-35
John 17:20-23