John Gill Commentary 2 John 1:3

"Grace, mercy, peace shall be with us, from God the Father, and from Jesus Christ, the Son of the Father, in truth and love." — 2 John 1:3 (ASV)

Grace be with you, mercy [and] peace
This form of salutation, or wish and prayer for the blessings mentioned,

from God the Father, and from the Lord Jesus Christ ,
is the same used by other apostles; see (1 Timothy 1:2) (Jude 1:2) and (See Gill on Romans 1:7). Only it is added here with respect to Christ, that he is

the Son of the Father in truth and love ;
which is mentioned by the apostle to confirm the deity of Christ, which is plainly implied in wishing for the above things equally from him, as from the Father; and to oppose and confront some heretics of those times, who denied the true and proper sonship of Christ; and therefore he calls him, "the Son of the Father", the only begotten of the Father; and that "in truth", or truly and properly, and not in a figurative and metaphorical sense, as magistrates are called the sons of God, and children of the most High, by reason of their office; but so is not Christ, he is God's own Son, in a true, proper, and natural sense.

And he is so "in love"; he is his well beloved Son, his dear Son, the Son of his love; as he cannot otherwise be; since he is not only the image of him, but of the same nature, and has the same perfections with him.