These similar sounding words are both from the same Latin root. I have some sympathy with the idea of co-herence being ‘hanging together’ – the result of consumption of the text, for the ‘hangings’ seem to be in the body of the consumer. Does the text co-inhere with its incarnate form after consumption? (Borrowing that similar sounding word from Charles Williams).
Cohesive on the other hand suggests the original meaning of the shared root, glue – how does the text appear to be glued to itself outside of consumption, i.e. as an object of observation. The observable form of the text is most obvious in nested structures – letter wise, word-wise, phrase-wise, and in larger macro forms. For instance the assonance of Psalm 1:1 – ‘asheri ha’ish ‘asher, or the circles of Psalm 51 – still there even if we haven’t seen them, each group of circles surrounding a core repetition – 3 times – of God’s righteousness.
Or take this as a third example, the thread of a cognate word-set within an epic poem like Job. E.g. spoken what is ‘right’ (Job 42) – that word ‘right’ does not hang together with the other 14 uses of the Hebrew that are visible in the text all of which are used as ‘establish’ or ‘prepare’ something.(see the comments at the above link).
If – and it is a big ‘if’ – the text is cohesive then to allow it to stick within a consumer (avoiding the hanging metaphor in case I choke on my own associations), we must pay attention to the sound of the original. The only way to do this is to dramatize it – speak it – and hear rather than dissect. Then not only will we consume the word but it will also consume us.
Of course, if the text is incoherent then we are chasing our tails. Lots of people have written off Job as incoherent. Most people read Psalm 51 as about repentance – but that is not the concept that is circled, and translations of assonance are nearly impossible, so micro-word-play, the foundation of cohesion, is lost.But - and it is a little but, I didn't put in any of the links to the examples I noted - and those links are still valid observations worth revisiting. The will test our faith that the Scriptures co-inhere - with what? In themselves - a stretch - in tradition, yes, in truth - how would we who are divided know even if we saw it? Oh and by the way, there is lots on Job at my other blog.