A.T. Robertson Commentary Luke 12:36

"and be ye yourselves like unto men looking for their lord, when he shall return from the marriage feast; that, when he cometh and knocketh, they may straightway open unto him." — Luke 12:36 (ASV)

When he shall return from the marriage feast (ποτε αναλυση εκ των γαμων). The interrogative conjunction ποτε and the deliberative aorist subjunctive retained in the indirect question. The verb αναλυω, very common Greek verb, but only twice in the N.T. . The figure is breaking up a camp or loosening the mooring of a ship, to depart. Perhaps here the figure is from the standpoint of the wedding feast (plural as used of a single wedding feast in Lu 14:8), departing from there. See on Mt 22:2.

When he cometh and knocketh (ελθοντος κα κρουσαντος). Genitive absolute of the aorist active participle without αυτου and in spite of αυτο (dative) being used after ανοιξωσιν (first aorist active subjunctive of ανοιγω).