Shakespeare often reused images and metaphors, stealing from himself. The simile in Friar Lawrence's musing from Romeo and Juliet,
And in their triumph die, like fire and powder,
Which as they kiss consume.
is echoed in the metaphor of the third quatrain of Sonnet 73.
In me thou see'st the glowing of such fire
That on the ashes of his youth doth lie,
As the death-bed whereon it must expire,
Consum'd with that which it was nourish'd by.