In this chapter, John Owen talks about what mortification truly IS. I wanted to break this chapter into 2 parts, because I think this paragraph has enough weight to be considered on its own. He analogizes sin being crucified in our lives to a man being crucified on a cross. Here's the paragraph, and it's a powerful one:
As a man nailed to the cross he first struggles and strives and cries out with great strength and might, but, as his blood and spirits waste, his strivings are faint and seldom, his cries low and hoarse, scarce to be heard; when a man first sets on a lust or distemper, to deal with it, it struggles with great violence to break loose; it cries with earnestness and impatience to be satisfied and relieved; but when by mortification the blood and spirits of it are let out, it moves seldom and faintly, cries sparingly, and is scarce heard in the heart; it may have sometimes a dying pang, that makes an appearance of great vigor and strength, but it is quickly over, especially if it be kept from considerable success. This the apostle describes, as in the whole Chapter, so especially Romans 6:6.