A.T. Robertson Commentary 1 John 2:24

"As for you, let that abide in you which ye heard from the beginning. If that which ye heard from the beginning abide in you, ye also shall abide in the Son, and in the Father." — 1 John 2:24 (ASV)

As for you (υμεις). Emphatic proleptic position before the relative ο and subject of ηκουσατε, a familiar idiom in Joh 8:45; 10:29, etc. Here for emphatic contrast with the antichrists. See 1:1 for απ' αρχης (from the beginning).

Let abide in you (εν υμιν μενετω). Present active imperative of μενω, to remain. Do not be carried away by the new-fangled Gnostic teaching.