1 John 2:5

ἡ ἀγάπη τοῦ Θεοῦ, “the love of God,” is ambiguous like אַהֲבַת יְהֹוָה, amor Dei, l' amore di Dio, l'amour de Dieu, die Liebe Gottes. It might be objective genitive, “love for God,” “die Liebe zu Gott” (Rothe). But the believer's love for God is never perfected in this life. The genitive is subjective (cf. 1 John 4:9), amor Dei erga honunem, per Christum nobis reconciliatus (Bengel), and the idea is that the redeeming love of God has attained its end in the man who observes His Word. Cf. Isaiah 53:11. St. Augustine understands “the love of God” as His love for sinners, a forgiving love like that of Jesus when He prayed on the Cross “Father, forgive them”. “What is the perfection of love? It is both to love one's enemies and to love them in order that they may be brethren.” By cultivating a love like this we get to know that we know Him. ἐν τούτῳ (b) points forward to ὁ λέγων, κ. τ. λ., introducing a second assurance. It is not enough to know Him; we must be sure of continuing in fellowship with Him, of “abiding in Him” to the end. This assurance comes by “walking even as He walked”; i.e. the conformation of our lives to His is an evidence of our abiding interest in Him, our vital union with Him. We get like Him by imitating Him, and our likeness to Him is an irrefragable evidence to ourselves and the the world that we are His, as a son's likeness to his father proves their relationship. ὀφείλει, “is bound,” “ist schuldig” (Rothe), of moral obligation. The claim (λέγων) must be honourably attested. αὐτὸς in this section refers grammatically to Jesus Christ 1 John 2:1-2). The change of pronoun (ἐκεῖνος) does not imply a change of person, since here as in 1 John 3:3; 1 John 3:5; 1 John 3:7; 1 John 3:16; 1 John 4:17, ἐκεῖνος is not a mere pronoun. It is used like ille, and signifies “that great One,” “the Master”. Cf. 2 Timothy 2:12-13. περιπατεῖν, see note on 1 John 1:6. Aug.: “Perhaps He admonishes us to walk in the sea. Far from it! He admonishes us to walk in the way of righteousness.”