I saw evil angels contending for souls, and angels of God resisting them. The conflict was severe. Evil angels were crowding about them, corrupting the atmosphere with their poisonous influence, and stupefying their sensibilities. Holy angels were anxiously watching these souls, and were waiting to drive back Satan's host. But it is not the work of good angels to control minds against the will of the individuals. If they yield to the enemy, and make no effort to resist him, then the angels of God can do but little more than hold in check the host of Satan, that they should not destroy, until further light be given to those in peril, to move them to arouse and look to heaven for help. Jesus will not commission holy angels to extricate those who make no effort to help themselves. MYP 52.3
If Satan sees he is in danger of losing one soul, he will exert himself to the utmost to keep that one. And when the individual is aroused to his danger, and, with distress and fervor, looks to Jesus for strength, Satan fears he shall lose a captive, and he calls a re-enforcement of his angels to hedge in the poor soul, and form a wall of darkness around him, that heaven's light may not reach him. But if the one in danger perseveres, and in helplessness and weakness casts himself upon the merits of the blood of Christ, Jesus listens to the earnest prayer of faith, and sends a reinforcement of those angels which excel in strength to deliver him. MYP 53.1
Satan cannot endure to have his powerful rival appealed to, for he fears and trembles before His [Christ's] strength and majesty. At the sound of fervent prayer, Satan's whole host trembles.... And when angels, all-powerful, clothed with the armory of heaven, come to the help of the fainting, pursued soul, Satan and his host fall back, well knowing that their battle is lost.—The Review and Herald, May 13, 1862. MYP 53.2