Answer:
Communion is for believers, and even then it is to be for believers whose heart is right with God and with others. At our church we always take time for soul searching and for prayer before communion so that even the believers can come and take time to make sure all is right with God.
The Bible says: 1 Corinthians 11:27-30 Wherefore whosoever shall eat this bread, and drink this cup of the Lord, unworthily, shall be guilty of the body and blood of the Lord. But let a man examine himself, and so let him eat of that bread, and drink of that cup. For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord’s body. For this cause many are weak and sickly among you, and many sleep.