This question comes from a deconstructionist and literary perspective, so it’s not about the transubstantiation of the bread into the Body of Christ by God, but that of the symbols into information by the author.
Mark 14:22
And as they were eating, he took bread, and after blessing it broke it and gave it to them, and said, “Take; this is my body.”
Jesus isn’t a talking pitta bread so this is a symbol. On a basis that God’s symbols are real, not merely true.
Saint Paul explains the symbol:-
1 Corinthians 12:27
Now you are the body of Christ and individually members of it.
This produces a primary tautology: the body of Christ (the Church) is eating the body of Christ (the Eucharist)
The tautology is virtuous because it sets a boundary to and defines the reader’s inquiry. Which isn’t a rhetorical trick like in Matt Walsh’s ‘What is a Woman?’ or Theresa May’s ‘Brexit-is-Brexit’
What it’s circumscribing is a eucharist that organically bonds us into Christ, realizes our participation in Christian life, unites the Church, and wherein we sustain one another whilst ourselves being nourished by the covenant.
The (non-canonical) Gospel of Thomas put it more concisely:-
[Log.7] Jesus said, "Blessed is the lion that's eaten by a human and then becomes human, but how awful for the human who's eaten by a lion, and the lion becomes human."
Saint John explains the symbol:-
John 1:14
And the Word became flesh and dwelt among us
This produces a secondary analogy (via recursion): the body of Christ is the scripture (because the Word's words are the Word)
The analogy generates information:-
- the scripture is to the Word what our body is to our spirit
- reading the scripture is as vital as eating
- the scripture can’t contradict itself any more than we can swallow two bites at once
- the scripture is a reproducible, non-diminishing good
- the scripture is inspired by God’s breath like Adam is animated by God’s breath
- the scripture should be interpreted communally not in isolation
- the scripture survives dismemberment and deletion, through translation
Any exposition drawn from the analogy might need tidying up or be capable of misinterpretation, or be too hazardous to draw at all - but the analogy itself is virtuous and upheld in ancient and modern liturgy (note below).
The tautology and the analogy aren’t in conflict or mutually-exclusive, neither is missing from either apostle, neither is the sole point of what Paul or John say, and both can be found in other passages including in the OT - it’s that these are their centres.
The question is from a structural-compositional perspective: why does Paul give the tautology priority over the analogy?
There is a type of answer that “it’s to prioritize the life-of-the-church over the study of the words”, which isn’t what I’m asking about. That’s redundant because the words say not to do it. A productive answer would be something like that the tautology was the best way to limit the analogy from a specific form of misinterpretation.
Was it to head-off contentions against the material world?
NOTES
re. the analogy in ancient liturgy there is the verbum domini / deo gratias formula
The Apostolic Constitutions (375AD) take the word as including the written word:-
https://archive.org/details/constitutionesa00conggoog/page/n304/mode/2up
Nam quid tibi deest in verbo Dei?
https://archive.org/details/constitutionesa00conggoog/page/n304/mode/2up
μη ἀκουειν των ἀναγιγνωσκοντων - των διδασκοντων τον του Κυριου λογον