What does Mark 14:40 mean?

Jesus is praying in the garden of Gethsemane the night before the crucifixion. Twice He's asked Peter, James, and John to stay up and watch and pray (Mark 14:34, 38). He doesn't ask them to pray for Him; He knows His future is decided even as He prays that God will change it (Mark 14:35–36). He wants them to pray that they can resist temptation in the time to come (Mark 14:38).

One of Satan's most effective strategies is to make our "eyes heavy" to his devastating work. While it's paranoid to think there is a demon behind every bush, it's also foolish to ignore the possibility that we will be confronted with spiritual warfare. Paul calls us to not be "ignorant of [Satan's] designs" (2 Corinthians 2:11). Peter says that Satan "prowls" and "seeks someone to devour" (1 Peter 5:8), showing that Satan is strategic in his attacks. It's certainly easier to attack someone who doesn't believe you're a threat. And, of course, when they're tired from a long day and full of food, as the disciples are.

Prayer to God makes a strong defense against the enemy. After the transfiguration, Jesus comes down the mountain with Peter, James, and John to find the rest of the disciples arguing with the scribes because the disciples could not free a boy from a dangerous demon (Mark 9:14–18). Jesus expels the demon, and the disciples ask why they were powerless. Jesus says, "This kind cannot be driven out by anything but prayer" (Mark 9:29).

Prayer isn't just to tell God what we want or ask for help when we get what we don't want. It's also designed to prepare us for spiritual battle. God is willing to equip us to fight temptation and the effects of the enemy. We should take advantage of His offer.