The first few verses of this are in the Book of Order, and are read whenever communion is given within the Presbyterian Church. The text used stops at verse 26.

Beyond that is Dragons, and there we are going.

1 Corinthians 11:23-29

23For I received from the Lord what I also handed on to you, that the Lord Jesus on the night when he was betrayed took a loaf of bread, 24and when he had given thanks, he broke it and said, “This is my body that is for you. Do this in remembrance of me.” 25In the same way he took the cup also, after supper, saying, “This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me.” 26For as often as you eat this bread and drink the cup, you proclaim the Lord’s death until he comes.

27Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be answerable for the body and blood of the Lord. 28Examine yourselves, and only then eat of the bread and drink of the cup. 29For all who eat and drink without discerning the body, eat and drink judgment against themselves.

via Daily Lectionary Readings — Devotions and Readings — Mission and Ministry — GAMC.

From verse 27 there are some warnings. Here theologians have argued — from those who say that discerning the body and blood means they literally become the body and blood of Christ — transmuted from bread and wine. I’m reformed. we say it’s a metaphor, a symbol. From the Book of order (yes, we have a liturgy for communion, and I’m quoting from memory)

“May this bread and wine be for us the body and blood of our Lord Jesus Christ”

But there are three warnings: one to a verse. And they do not need much theological disputation.

1. We must take the bread and wine in a worthy manner. No gluttony — meals should be shared or symbolic. Not without modesty, not without dignity.
2. We should examine ourselves. My Catholic friends have turned this into a separate institution of confession (which they now call reconciliation, which confuses this Protestant). Within the Protestant service, we are called to examine ourselves and confess our sins, either by liturgical prayer “We have done what we ought not done, We have not done what we ought to have done”.
   
3. We must discern the purpose of this. We must be of age and be able to understand what is going on. We must do it as a church… body has at least three meanings (Christ, his church, the incarnate and now risen body of our Lord)

As Paul said, wait for each other, make the meal a symbolic one, and concentrate on the work of Christ on the cross, and doing good. For here the doctors of the church do not dispute.