A.T. Robertson Commentary Jude 1:22

"And on some have mercy, who are in doubt;" — Jude 1:22 (ASV)

And on some (κα ους μεν). Demonstrative plural of ος μεν--ος δε (ους δε, below), not the relative ους, but by contrast (μεν, δε). So Mt 13:8.

Have mercy (ελεατε). Present active imperative of ελεαω (rare form in Ro 9:16 also for the usual ελεεωMatthew 9:27). But A C read ελεγχετε, refute, in place of ελεατε. The text of this verse is in much confusion.

Who are in doubt (διακρινομενους). Present middle participle of διακρινω, in the accusative case agreeing with ους μεν, though K L P have the nominative. If the accusative and ελεατε is read, see Jas 1:6 for the idea (doubters). If ελεγχετε is read, see Jude 1:9 for the idea (disputers).