That this Letter was the actual work of the Apostle John,
the son of Zabdi, has been abundantly testified from the very
earliest times.
Some modern critics have doubted it, on the ground of
internal evidence. But a calm survey of the whole case does not
bear out their objections. Dr. Salmon well says that no
explanation of the origin of the Epistle fits the facts so well
as the one which has always prevailed. It seems to have been
addressed to the Church at large, with perhaps special reference
to the Churches in Roman Asia.
The connexion between this Letter and the fourth Gospel
is "intimate and organic. The Gospel is objective and the Epistle
subjective. The Gospel suggests principles of conduct which the
Epistle lays down explicitly. The Epistle implies facts which the
Gospel states as historically true."
This Letter appears to have been written from Ephesus,
and critics have usually assigned 95 A. D., or some other year
equally late in the Apostolic age, as the probable date of its
composition. On the other hand the internal evidence points to a
date immediately preceding the destruction of Jerusalem in 70
A.D. See 2:8 (last clause); 2:18; 4:3; and note the expectation
of a speedy Coming of Christ (2:28; 3:2)--an expectation which
seems almost to have ceased in the early Church after that date.