"Present your bodies a living and holy sacrifice, acceptable to God, which is your spiritual service of worship." Romans 12:1
I am reminded that today is yet another day with many opportunities to worship God. My body is to be given to God on this day - whatever condition it is in. I will have opportunity to pray, to praise, and to let the members of my body be used for God and by God. Even if I am sad or worse - in agony - I still have this directive from God to present my body as a living sacrifice to Him. This is not to say that I cannot pray for healing, or cry out to God in my pain, but we have the choice before us: to worship Him in the midst of a diseased body or not.
This is a mystery: to worship in spite of darkness and evil which appears to prevail. "For now we see in a mirror dimly, but then face to face; now I know in part, but then I shall know fully just as I also have been fully known." 1 Corinthians 13:12