Lo in the orient when the gracious light
Lifts up his burning head, each under eye
Doth homage to his new-appearing sight,
Serving with looks his sacred majesty;
And having climbed the steep-up heavenly hill,
Resembling strong youth in his middle age,
Yet mortal looks adore his beauty still,
Attending on his golden pilgrimage:
But when from highmost pitch, with weary car,

 The sun, even in middle age, resembles a strong youth. This will apply to the young man whose beauty and strength will endure, at least for a while, like the sun.
Sonnet 7