Rev. rightly gives the force of the article, the strong man. Christ is not citing a general illustration, but is pointing to a specific enemy - Satan. How can I despoil Satan without first having conquered him?
Goods (σκεύη)
The word originally means a vessel, and so mostly in the New Testament. See Mar 11:16; Joh 19:29. But also the entire equipment of a house, collectively: chattels, house-gear. Also the baggage of an army. Here in the sense of house-gear. Compare Luk 17:31; Act 27:17, of the gear or tackling of the ship. Rev., lowered the gear.