The apostle Paul tells us that our Lord instituted the Supper on the night He was betrayed. The indications from the gospels are that He served the elements of that Supper to his betrayer, Judas, who was already under the influence of Satan himself. And Jesus knew this.
At the first celebration of this Supper—and it was a celebration, for Jesus’ gave thanks—the table was marred by the presence of a false one. Jesus knew this, and He established the sacrament anyway. Let God be true, and every man a liar. The sacraments are what God says about them, and never what men say about them—which is a good thing, considering the history of controversy that has swirled around what we are doing here now. We are told to take, eat, and not take, speculate.
As we think about the presence of a traitor at the first Supper, this makes us think of all the traitors present at this Table since that time, down to the present. But instead of looking around us for a Judas, we need to understand that each of us brings more than enough of Judas to the table ourselves.
But know that the sin of Judas was not that he was at the table, sinful as he was. His great sin was that he departed from that table and went out into the night. If you obstinately cling to your sin, even if you remain in your seat, you are following him there. If you confess the goodness of God to you in His free forgiveness, then God is here giving you nourishing bread and rich wine.
So come, and welcome, to Jesus Christ.