The Human Body as a House
If you read what we had to say about "Clothing," then you already know that our speaker is super preoccupied with the idea that outward appearances aren't as important as having a rich, inner spiritual life. That's why he compares his body to a house that's been pimped out on the outside but is totally falling apart on the inside. In other words, he's worried that he's been way too shallow and has been neglecting his inner soul.
- Line 4: After pointing out that his soul is suffering inside his body, the speaker accuses it of "painting" its "outward walls so costly gay." When he talks about his body as if it's a house that's been richly decorated ("painted") on the outside, he suggests that he's way too concerned with outer appearances.
- Lines 5-6: Here, the speaker further develops the body = a house metaphor. He asks the following question: "Why so large cost, having so short a lease, / Dost thou upon thy fading mansion spend?" In other words, why spend so much time, effort, and money on a body ("aging mansion") that's just going to die because life is so short? The idea is that the mortal body is like a house and we all just rent our bodies for a short time until we move out (die). By the way, the speaker of the sonnets says something similar in Sonnet 13 when he warns his younger friend that he should hurry up and have some kids because he's just got a "lease" on his "beauty" for just a short amount of time (Sonnet 13, line 5).