"But thy eternal summer shall not fade."-Explain

This line is taken from 'Shall I Compare Thee' written by William Shakespeare. The poet here boldly affirms the perpetual continuity of his friend's summer despite the ravages wrecked by time.

   The 'eternal summer' of the poet's friend who is 'the world's fresh ornament' is referred to here.

     Here 'eternal summer' means the youthful beauty which is superior to the charm of the seasonal summer. The beauty of the poet's friend is not subject to mutability that characterizes all earthly things. It defies the onslaughts of all-devouring time. It will never fade, because it will be given an eternal lease of life by poet's lines. The youth's summer is not 'eternal' in itself, but only in so far as it is caught and preserved in Shakespeare's verse. The poet's friend is the fairest of all. Nothing can steal away his summer nor defile the sublimity that his friend is possessed of. His beauty is to continue eternally.