10 So then here to; “The flesh lusts against the Spirit, and the Spirit against the flesh.” And what means, “So that you cannot do the things that you would”? For here is the peril with one who understands it amiss. Be it now my office to explain it, howsoever incompetent. “So that you cannot do the things that you would.” Attend, you holy ones, whosoever you are that are fighting. To them that are battling do I speak. They who are fighting, understand; he that is not fighting, understands me not.
Yea, he that is fighting, I will not say understands me, but anticipates me. What is the chaste man's wish? That no lust should rise up in his members at all opposed to chastity. He wishes for peace, but as yet he has it not. For when we shall have come to that state, where there shall rise up no lust at all to be opposed, there will be no enemy for us to struggle with; nor is victory a matter for expectation there, for that there is triumphing over the now vanquished foe. Hear of this victory, in the Apostle's own words; “This corruptible must put on incorruption, and this mortal must put on immortality.
Now when this corruptible shall have put on incorruption, and this mortal shall have put on immortality; then shall be brought to pass the saying that is written, Death is swallowed up in victory.” Hear the voices of them that triumph; “O death, where is your contention? O death, where is your sting?” You have smitten, you have wounded, you have thrown down; but He has been wounded for me who made me. O death, death, He who made me has been wounded for me, and by His Death has overcome you. And then in triumph shall they say, “O death, where is your contention? O death, where is your sting?”
Source: Sermons on Selected Lessons of the New Testament (New Advent)