And Saul's servants said unto him, Behold now, an evil spirit from God troubles you.
All Commentaries on 1 Samuel 16:15 Go To 1 Samuel 16
Tertullian of Carthage
AD 220
The devil has power that might be called his own, only over such as no longer belong to God, the heathen whom he considers once for all as a drop in a bucket, as dust on the threshing floor, as spittle in the mouth—and, as such, totally handed over to the devil as a quite useless possession.
Otherwise, he may do nothing by his own right, against those who dwell in the house of God, because the cases that are noted in Scripture show us when—that is, for what reasons—he may touch them. The right to tempt a person is granted to the devil, either for the sake of a trial, as in the texts cited above, whether God or the devil initiates the plan, or for the purpose of the reprobation of a sinner, who is handed over to the devil as to an executioner. This was the case with Saul. “The spirit of the Lord departed from Saul, and an evil spirit from the Lord troubled and stifled him.” Again, it may happen in order to humble a person, as Paul tells us that there was given him a thorn, a messenger of Satan, to buffet him, and even this sort of thing is not permitted for the humiliation of holy ones through torment of the flesh, unless it be done so that their power to resist may be perfected in weakness.
