Jamieson, Fausset and Brown on 1 John 2:28

28. little children--Greek, "little sons," as in 1Jo 2:12; believers of every stage and age.

abide in him--Christ. John repeats his monition with a loving appellation, as a father addressing dear children.

when--literally, "if"; the uncertainty is not as to the fact, but the time.

appear--Greek, "be manifested."

we--both writer and readers.

ashamed before him--literally, "from Him"; shrink back from Him ashamed. Contrast "boldness in the day of judgment," 1Jo 4:17; compare 1Jo 3:21; 5:14. In the Apocalypse (written, therefore, Bengel thinks, subsequently), Christ's coming is represented as put off to a greater distance.