For this is the message - Margin, “commandment.” In the received text, this is ἀγγελία angelia - “a message brought;” in several manuscripts, and in later editions, it is ἐπαγγελία epangelia - “annunciation, announcement;” an order given, or a commandment, Acts 23:21. It is not very material which reading is followed. The word “command” or “rule” would express the sense with sufficient clearness. The reference is to the law given by the Saviour as a permanent direction to his disciples.
That ye heard from the beginning, that we should love one another - See the John 13:34-35 notes; 1 John 2:7 note.