I have an enormous amount of miscellaneous poetry, some passive, some active, in my head at any one time. The passive stuff needs some sort of key to trigger it, like a phrase or image to start the memory processes. Active stuff is almost hardwired for instant recall, such as the lines from the end of Part One of Coleridge's 'Christabel'. (I once knew someone who could recite the whole of T.S Eliot's 'The Waste Land', but that was just showing off!) Remembering, for me, is as much a matter of rhythms and imagery as the actual words. Sometimes the words that I think I remember, even when I'm convinced I remember them precisely, turn out to be slightly different from the actual words of the poet. On one or two occasions when I've discovered this I've still been convinced that my version is was the poet should have written (but that's worse than showing off!).
Here are some lines I thought I'd remembered precisely though I had no memory of their context in a poem:
In elder days of art
Men wrought with utmost care
Each remote and unseen part
For the gods are everywhere.
The lines resonated so I 'remembered' them. But the only thing I could remember about them was that they were from Longfellow. So I looked them up. Here, from Longfellow's poem 'The Builders', are the original lines:
So my memory was inaccurate. I'd internalised something that did not have a precise external correlate. But the idea and the form of its expression were what stayed with me. Looking at the rest of the poem I find I don't much care for what Longfellow does with the idea beyond this stanza. The poem as a whole has a rather moralistic tone and , as much as I can also endorse the idea of making the house "where the gods may dwell" I find his expression overall fraught with pseudo-Blakean imagery but tending more towards the homily than the visionary.
In the elder days of Art,
Builders wrought with greatest care
Each minute and unseen part;
For the Gods see everywhere.
So I wish I'd never looked it up. I'm sure I didn't get the verse from reading the whole poem originally and must have seen that stanza quoted somewhere. Perhaps this shouldn't affect the value of the fragment as an inspiring idea. But, somehow, it does.