The way an allusion gets you to think of Marvel is different from the way a command does
"Think of the line 'let us roll all of our strength and all our sweetness up into one ball' in Marvel's poem!"
"Would it have been worth while,
To have bitten off the matter with a smile,
To have squeezed the universe into a ball
To roll it toward some overwhelming question.." (from Prufrock)
Both sentences 'objectively suggest' (i.e. suggest in a way that doesn't depend on suitable authorial intention) something like, that you should think of the line from To His Coy Mistress.
But they seem quite different e.g. we don't talk about obeying poems, and there are way too many suggestive things in poems for us to try to think about everything that's suggested for thought simultaneously.