So you feel you have ‘the calling’ and so you want to start a Group: fine. Whoever is going to join you will have to be of the same understanding as you in regards to the Gospel. Here the creed comes in. If ten out of twelve believe that Jesus was the son of God, then two of the twelve are not of the same creed. It is then clear that the two should find a group which is in agreement with their disbelief, as it is clearly written that Jesus is the son of God. So creeds are essential to confirm your group consists of actual Christians and/or Believers, and not of jokers. This is why churches use creeds.