The breaking of bread among the first Christians differed quite noticeably from the forms of it that we know today. In those days it included a fraternal meal, which today is found in Christian gatherings only rarely, if at all. Among the first Christians, as one can see, the custom of Jewish ritual meals was still preserved, similar, for example, to the Sabbath meal or the Passover seder, which began with prayer and the blessing of bread and wine and then smoothly flowed into the joyful feast without which no Jewish holiday is imaginable. And, as one can see, some of the newly converted, who only recently had been Gentiles, did not look very deeply into the meaning of the breaking of bread as the sacred gathering of the Church. For them it was simply a cheerful gathering of fellow believers, while the reality of the risen Christ, present in this gathering and sanctifying it by His presence, was apparently more of an abstraction for them.
Of course they understood for whose sake they had gathered, but one can think that they perceived this more as a symbol or allegory than as a genuine reality. Perhaps they thought that the Savior's words, spoken by Him at the Last Supper, meant not the kind of remembrance that makes the eternal present, but the kind that calls to mind something that once existed in the past but no longer exists now.
And after remembering the Teacher and blessing His memory, they began to celebrate with a sense of duty fulfilled. They most likely did not think at all that the risen Christ was still quite truly sitting with them at the same table, that the Church is not an organization created by Him but His spiritual body, His own continuation in our world, which is being transfigured but is not yet transfigured.
And therefore, according to the apostle's word, they became ill and died. Of course, the sacred meal was not killing them, as some commentators have sometimes interpreted Paul's words. What was killing them first of all was their separation from the Church as the body of Christ, from that source of life beside which they were standing but from which they were not drinking. Of course, God does not abandon anyone, even those who do not believe in Him very much. Everyone who lives is alive by His power.
But after baptism God brings the newly converted person to a new source, which must become the foundation of his whole further life. The previous way of spiritual life, and of life in general, is no longer for him. And if the newly converted person neglects this new source, whether consciously or simply through frivolity, irreversible degradation can occur both in his spiritual life and in his life as a whole. The kind from which one can become ill and die.
