First and Second John both describe the love command as something heard “from the beginning” and define faithful walking through love and obedience.

Leviticus commands love of one’s neighbor; 2 John says the command heard from the beginning is that believers love one another and defines love as walking in God’s commandments. The later letter develops neighbor-love into a Christ-shaped community command, but it does so thematically rather than by formally citing Leviticus 19:18.

Deuteronomy joins loving YHWH, walking in his ways, and keeping commandments; 2 John likewise defines love through walking according to God’s commandments. Love and obedience remain inseparable covenant categories.

Jesus gives his disciples the new commandment to love one another; 2 John says he is not writing a new commandment but the command heard from the beginning: love one another.

Jesus links love for him with keeping his commandments; 2 John defines love as walking according to God’s commandments.

First John says love for God is expressed by keeping his commandments; 2 John similarly says love means walking according to his commandments.

Second John rejoices over the lady’s children “walking in truth”; Third John says the elder has no greater joy than to hear that his children walk in truth. The approved evidence supports the connection at its current confidence level without turning thematic continuity into a quotation claim the text does not make.