However, youthful beauty peaks and fades, making it impossible to retain. It is fleeting, no matter how outwardly beautiful one is. The subject's beauty comes directly from heaven, as all true beauty does, from the author of perfection:

That is true beautie: that doth argue you
to be divine and borne of heavenly seed:
deriv'd from that fayre Spirit, from whom al true
and perfect beauty did at first proceed.

The theme, therefore, is that inner beauty has far greater significance than outward appearances and is a gift from a perfect Creator.

In this poem, the speaker addresses his beloved. He says that other men tell her that she is physically beautiful, and she can verify this in the mirror, but her "virtuous mind" and "gentle wit" is what he finds truly beautiful about her. Eventually, he claims, her external beauty will fade—her body will age and wither—so the only true beauty is the one contained by the ultimately frail body. Her soul is what connects her to the divine, and this is where her true beauty lies and where it first originated, long before her body was even created. Therefore, one theme of this poem is that all physical beauty is temporary and liable to corruption, but beauty of spirit is permanent and eternal. Another, related, theme is that the physical body is but an earthly house for the soul, and the soul will live on when that house has decayed.

The theme of "Sonnet 79" by the Elizabethan poet Edmund Spenser is the true meaning of beauty. Spenser makes a distinction between eternal beauty, that which is given by God, and the more fleeting, earthly beauty that will one day fade away. In "Sonnet 79" the speaker gladly acknowledges the immense physical beauty of his lover. At the same time, however, he gently reminds his beloved that what makes her really beautiful is her intelligence and virtue:

Men call you fair, and you do credit it,

For that your self ye daily such do see:

But the true fair, that is the gentle wit,

And vertuous mind, is much more prais'd of me.

For all the rest, how ever fair it be, Shall turn to naught and lose that glorious hue: But only that is permanent and free From frail corruption, that doth flesh ensue. That is true beauty

The poem presents a "dialog" between Spense and his lady.  He attempts to immortalize her by writing her name in the sand, but the waves (time) relentlessly erase what he writes.  He writes again, with the same results.

The poem them switches to his lady who tells him that he is foolish to attempt to make immortal that which is temporal; she will pass just as the writing in the sand.

Spenser then reenters the conversation and tell her that although there is a physical/temportal part to her nature, his verse will make her immortal.

He summarizes the theme in the final couplet:  although things physical may perish, the spiritual nature of their love will transcend death and even grow.