What blows my mind is that some people think all they have to do is get baptized as a baby, go to Mass every chance you get, go to confession every chance you get, receive communion every chance you get, give to the poor, get confirmed, do good deeds, do works of mercy, obey the commandments, believe everything the Pope and bishops tell you, get last rites before you die - if you're lucky enough, and STILL have no assurance that you will go to heaven when you die.
When Jesus said to eat his body and drink his blood he was talking about receiving him, believing in him and trusting in him as Savior by faith. Believing that when he died on the cross he paid for ALL our sins and because of God's grace we are saved through faith in HIM. The Eucharist was as Jesus said, "In remembrance of him.". Participating in the communion service is joining with the body of Christ to celebrate and remember what he did for us, by his shed blood we are redeemed. His body was broken for us and his blood was shed for our sins in full payment so that NOTHING I can do needs to be added to that sacrifice. The Apostle John, who also wrote the Gospel According to John where the account of Jesus' words about eating his flesh and drinking his blood is told, tells us in I John 5:13, "These things have I written unto you that believe on the name of the son of God so that you may know that you have eternal life and so that you may believe on the name of the son of God." This do in remembrance of me.
As often as you eat this bread and drink this cup you do show the Lord's death until he comes.
Those who think that are only fooling themselves.
The Jews had a "confession" of sorts. They told their sins to their High Priest and brought "sin offerings." Confession didn't come out of thin air, it was another legacy of Judaism.