This is a poem in which Spenser talks in disparaging terms about a woman who uses her beauty to tempt him close to her so that she can prey on him. The poem begins by pointing out that the panther, finding that his body is beautiful but that his face scares animals away, hides his face to allure animals to come close to him so he can them kill and eat them. In the same way, Spenser argues, this woman uses exactly the same strategy:
For with the goodly semblance of her hew
She doth allure me to mine owne decay,
And then no mercy will unto me shew.
He is clearly describing a woman who is using her beauty to exploit and destroy the speaker's character, and who, when she has him entranced and subject to her beauty, shows him no mercy as she leads him on to his "decay." The speaker deplores the way that what is so beautiful has been made to draw in and ruin others, but ends with the consoling thought that beauty finds its true union with mercy, and remembering that God is the author of both helps us cope with such situations.