With Sonnet 108, William Shakespeare loops back into sentiments expressed intermittently since Sonnet 76, but particularly again recently in Sonnet 105: I have essentially said it all, there is nothing I can do other than repeat and reiterate and rephrase the praises I have sung and continue to sing for you. What it also picks up from Sonnet 105 is the religious tone this set with a there still fairly oblique reference to the Holy Trinity. This was already amplified, though subtly, in Sonnet 106, and here finds a whole new level of what may potentially be perceived as impudence, if looked on from a devoutly religious perspective.
What it also does – and this may in some respects for our observation be most directly relevant – is to tell his young lover yet again that he is showing signs of age, but that to him, Shakespeare, this doesn't matter.

Of all the poems in the collection first published in 1609, Sonnet 107 most clearly and most compellingly seems to refer to external events that shape Shakespeare's world.

Because of this, it takes up a pivotal position in the canon, since it may therein hold clues to both its date of composition and to the person it is addressed to. And while there is little doubt in most people's mind that its references are indeed intentional and allude to some momentous occasion that has passed off signally better than anyone at the time would have predicted, and that in the ensuing calm and peace our poet feels that his love and his poetry have been given a new lease of life, no-one can tell with absolute certainty just what Shakespeare is actually referring to or whom he is talking to, or even whether the two factors are directly or only indirectly linked, or not at all.

There are, however, significant clues, and so much of our discussion of this sonnet will concern itself with what these are and what they mean for our reading of this and the other sonnets in the series.

Sonnet 106 sees Shakespeare return to eulogising his young lover in outwardly straightforward terms. And rather than looking ahead to times to come when his poetry will continue to pay tribute to his love long after both he and his lover have gone, as several of the other sonnets have done, he here casts his eye back to the past through the lens of the poets who have talked about the people of their day, and comes to the conclusion that they were doing just as he is doing now: trying to express the epitome of beauty. But since this had not yet been reached, because the young man of his love had not yet been born, they ended up not so much chronicling their age as predicting an age to come with his appearance in this world; and yet of course now that he is here, it is possible for Shakespeare and anyone who shares the privilege of being in his presence to admire him, but Shakespeare and his contemporaries still find it impossible to do him justice with their words.