Why "Guard" the Communion Table?

The cup of blessing that we bless, is it not a participation in the blood of Christ? The bread that we break, is it not a participation in the body of Christ? Because there is one bread, we who are many are one body, for we all partake of the one bread - 1 Corinthians 10:16–17

Whereas baptism acts as the New Covenant sign of initiation, communion acts as the ongoing covenant sign of belonging. In the Old Covenant, circumcision served as the sign of initiation which was given to those who have the blood of Abraham. In the New Covenant baptism serves as the better sign given to those who have the faith of Abraham. Similarly, in the Old Covenant, Passover served as the ongoing communal memorial for those who belonged to the covenant family. In the New Covenant, Jesus gathers with his apostles on the night of Passover to institute this new and better ongoing communal memorial for those who belong to the covenant family of faith. (If baptism acts as the wedding ring, sealing and identifying one as a member of a covenant, communion acts as marital intimacy, regularly picturing and acting out this covenant and union with Christ forevermore.)

It was no coincidence that Christ institutes the Lord’s Supper on the night of Passover. Christ, as the true passover lamb (1 Cor 5:7, Jn 1:29) whose blood would cover all those who have faith in Him and thus set the faithful free from slavery and to the promised land, instituted a new regular memorial and covenant meal, this time not only to be celebrated annually, but (we believe) weekly as a central element of our assemblies.

The Old Testament makes clear with severe warnings (Ex 12:43-49) that only those who had taken the initiating oath sign were allowed to take part in the covenant family meal; the same thing is true of the New Covenant meal.

Thus, we join the church throughout history in “fencing” or “guarding” the table. It is only recently in the history of the church that this hasn't been universally practiced. All "guarding” or “fencing” means is that we don’t invite anyone and everyone to take communion, but only those who have publicly identified themselves in baptism to Christ and his covenant (including children yet to be baptized). One does not have to be a member of King’s Fellowship to be welcome to the table; any member of Christ is welcome. No one is standing armed at the table! But we do join Paul in giving the warning for taking it in an unworthy manner (1 Cor 11:27-32).

This is where “excommunication” gets its name; removing someone from membership is seen historically as primarily, or firstly, removing them from the family communion table. As the verse above makes clear, taking part in the bread and the cup is a participation in/union with the body and blood of Christ, and it is a clear picture of the many being pictured as the one; therefore only those who are united to Christ are invited.