A.T. Robertson Commentary Mark 3:27

"But no one can enter into the house of the strong [man], and spoil his goods, except he first bind the strong [man]; and then he will spoil his house." — Mark 3:27 (ASV)

Spoil (διαρπασα). Plunder, compound verb, thoroughly ransack. Picture of Satan plundering the demons, the very tools (σκευη) by which he carried on his business. A reductio ad absurdum. Jesus is the conqueror of Satan, not in league with him.