Poor soul, the center of my sinful earth, (1)
When the speaker calls his body his "sinful earth," it seems like a reference to traditional Christian theology, which tells us that all human beings are sinful and flawed and are in need of salvation. Plus, by calling a body a sinful earth is a pretty big shout-out to the Book of Genesis (especially Genesis 2:7), where Adam (the first man) was made from dust, or earth. So basically, Shakespeare is kicking off this sonnet at the very beginning of human life on earth. Compare this to the final couplet, where the speaker makes a reference to Judgment Day (a.k.a. the end of the world). Talk about scope.
.......these rebel pow'rs that thee array, Why dost thou pine within and suffer dearth, (2-3)
The speaker of this sonnet says he wants to have a rich inner spiritual life but he's been struggling because his bodily desires are so overwhelming and powerful that he hasn't been paying enough attention to his soul. Hey, we've all been there buddy. We mean, it's really hard to care about your soul when you're chowing down on a Double Double at In N Out.
Buy terms divine in selling hours of dross;Within be fed, without be rich no more, (11-12)
So what's a guy like our speaker to do when his soul is in such lousy shape? Here, he says he believes that if he nourishes his inner spirit, he'll be able to kick it with God (the "divine") for all of eternity. Yep. That's just a little vague, Shmoopers. He never says exactly how he's going to go about nourishing his soul. We have a feeling it doesn't involve Double Doubles, sadly.