and whenever it takes hold of him, it throws him down, and he foams at the mouth, grinds his teeth, and he becomes rigid. And I asked your disciples to cast it out, but they were not strong enough.” Bible see other translations

“strong enough.” The Greek is ischuō (#2480 ἰσχύω), which means strength. This verse gives us a glimpse into the spiritual battle that can wage when demons live inside a body. It takes spiritual strength to cast them out. That strength comes from trust (Matt. 17:20), which is connected to one’s prayer life (Mark 9:29). Another example of strength in the spiritual battle is Revelation 12:8. The Devil and his demons wanted to remain in heaven, but they were not strong enough to fight against Michael and the angels. To say the apostles “could not” cast out the demon is correct, but not helpful, because then we have no idea why. The Greek is more helpful, saying that the spirit did not come out because the apostles were not spiritually strong enough. Spiritual power in the life of a believer is usually not a matter of either having it or not, it is usually a matter of how much power one has, and do we have enough to get the job at hand done for the Lord.

Commentary for: Mark 9:18