We do know that it originated from the night Jesus and his disciples were at the Last Supper, the night before Jesus is crucified:
1 Corinthians 11:23-26
23For I have received of the Lord that which also I delivered unto you, that the Lord Jesus the same night in which he was betrayed took bread: 24And when he had given thanks, he brake it, and said, Take, eat: this is my body, which is broken for you: this do in remembrance of me. 25After the same manner also he took the cup, when he had supped, saying, this cup is the new testament in my blood: this do ye, as oft as ye drink it, in remembrance of me. 26For as often as ye eat this bread, and drink this cup, ye do shew the Lord's death till he come
When we are receiving the juice and crackers at church, it's important to know what communion really is. We are remembering Jesus and giving thanks for our redemption. At the same time we are also embracing the common bond that we share with fellow believers. But the Bible also warns us of participating in communion without knowing Jesus and what this holy tradition really is about:
1 Corinthians 11:27-29
27 Therefore whoever eats this bread or drinks this cup of the Lord in an unworthy manner will be guilty of the body and blood of the Lord. 28 But let a man examine himself, and so let him eat of the bread and drink of the cup. 29 For he who eats and drinks in an unworthy manner eats and drinks judgment to himself, not discerning the Lord's body.
Some Churches have communion on a weekly basis and announce it at the end of the service. In their announcement, they don't even say to the congregation "If you are a believer and have given your life to the Lord, receive your communion. " They really need to convey this message to their congregation each time that they have communion. There might be new comers there or young children that may not understand what communion really means, that will participate.
Remember to not take the real meaning of communion lightly. Rejoice in the Lord and the precious blood he shed on the cross for our sins. And if you have Christ in your heart, then gladly participate in the wonderful holy tradition from the Last Supper called communion.