(Read Matthew 26:36-46.)
Jesus wants His disciple to pray with Him, to take part in something important with Him, but they can't because they keep falling asleep!
Has your body ever kept you from accomplishing spiritual things? Has some bodily weakness or temptation ever kept you from being all that you can be spiritually?
Christians focus quite a bit on the spirit, but we need to remember that God also created and cares about our body. He made us as whole persons and will eventually raise us back to life as whole persons, body and soul.
When we keep our bodies fit, eat right, and perform spiritual practices that keep our bodily temptations in check, we are honoring God.
Paul says he beats his body and makes it his slave (1st Corinthians 9:27). Jesus told us to fast (Matthew 6:16-18), one of the purposes of which is to learn to control our bodily urges.