If you want fellowship with the church, if you have not formally joined, there are two ways to do so. One is to pray in public, give money, show enthusiasm and fill out a card. The other is to do first things first--join the universal church--and then also fill out a card. An important part of joining the church is public confession. Why does the Lord want us to make a public confession? The Bible says, "The word is near you; it is in your mouth and in your heart," that is, the word of faith we are proclaiming: That if you confess with your mouth, 'Jesus is Lord,' and believe in your heart that God raised him from the dead, you will be saved. For it is with your heart that you believe and are justified, and it is with your mouth that you confess and are saved (Romans 10:8b-10). The heart believes and the mouth confesses. Both are necessary to salvation. Even the thief on the cross made his poor pitiful confession. That is why God wants us to fellowship with each other, get together and tell the world and tell each other--because with the mouth confession is made for salvation. My plea is for those who have never undergone the marvel of the regeneration of new birth to take this seriously. Remember you get into the ark through the door, and Jesus Christ is the door. If you reject the ark, you reject the door, and if you reject the door you perish in the flood.
