Τεκνία μου, ταῦτα γράφω ὑμῖν ἵνα μὴ ἁμάρτητε[1]. καὶ ἐάν τις ἁμάρτῃ, παράκλητον[2] ἔχομεν πρὸς τὸν πατέρα Ἰησοῦν Χριστὸν δίκαιον· 2 καὶ αὐτὸς ἱλασμός ἐστιν περὶ τῶν ἁμαρτιῶν ἡμῶν, οὐ περὶ τῶν ἡμετέρων δὲ μόνον ἀλλὰ καὶ περὶ ὅλου τοῦ κόσμου. 3 Καὶ ἐν τούτῳ γινώσκομεν ὅτι ἐγνώκαμεν[3] αὐτόν, ἐὰν τὰς ἐντολὰς αὐτοῦ τηρῶμεν. 4 ὁ λέγων ὅτι Ἔγνωκα αὐτὸν καὶ τὰς ἐντολὰς αὐτοῦ μὴ τηρῶν[4], ψεύστης ἐστὶν καὶ ἐν τούτῳ ἡ ἀλήθεια οὐκ ἔστιν· 5 ὃς δʼ ἂν τηρῇ αὐτοῦ τὸν λόγον, ἀληθῶς ἐν τούτῳ ἡ ἀγάπη τοῦ θεοῦ τετελείωται, ἐν τούτῳ γινώσκομεν ὅτι ἐν αὐτῷ ἐσμεν. 6 ὁ λέγων ἐν αὐτῷ μένειν ὀφείλει καθὼς ἐκεῖνος περιεπάτησεν καὶ αὐτὸς [οὕτως] περιπατεῖν.
My children, this I am writing to you in order that you might not sin. And if someone does sin, we have an advocate with the Father; Jesus Christ the Righteous. And He is propitiation for/concerning our sin, not for ours alone but also even for the whole world. And in this we know that we have known him, if we keep his commandments. The one who says that He has known him and does not keep his commandments, he is a liar and in (this one) the truth is not. But whoever keeps his word, truly in (this one) the love of God is made complete, in this we know that we are in him. The one who says to remain in him ought to walk just as he also walked.
7 Ἀγαπητοί, οὐκ ἐντολὴν καινὴν γράφω ὑμῖν ἀλλʼ ἐντολὴν παλαιὰν[5] ἣν εἴχετε ἀπʼ ἀρχῆς· ἡ ἐντολὴ ἡ παλαιά ἐστιν ὁ λόγος ὃν ἠκούσατε. 8 πάλιν ἐντολὴν καινὴν γράφω ὑμῖν, ὅ ἐστιν ἀληθὲς ἐν αὐτῷ καὶ ἐν ὑμῖν, ὅτι ἡ σκοτία παράγεται[6] καὶ τὸ φῶς τὸ ἀληθινὸν ἤδη φαίνει. 9 ὁ λέγων ἐν τῷ φωτὶ εἶναι καὶ τὸν ἀδελφὸν αὐτοῦ μισῶν ἐν τῇ σκοτίᾳ ἐστὶν ἕως ἄρτι. 10 ὁ ἀγαπῶν τὸν ἀδελφὸν αὐτοῦ ἐν τῷ φωτὶ μένει καὶ σκάνδαλον[7] ἐν αὐτῷ οὐκ ἔστιν· 11 ὁ δὲ μισῶν τὸν ἀδελφὸν αὐτοῦ ἐν τῇ σκοτίᾳ ἐστὶν καὶ ἐν τῇ σκοτίᾳ περιπατεῖ καὶ οὐκ οἶδεν ποῦ ὑπάγει[8], ὅτι ἡ σκοτία ἐτύφλωσεν τοὺς ὀφθαλμοὺς αὐτοῦ.
Beloved, it is not a new commandment I write to you but an old command which you had from the beginning. The old commandment is a word you have heard. Again a new command I write to you, which is true in him and in you, because the darkness is passing away and the true light is already shining. Whoever says he is in the light and hates his brother is in darkness until now. The one who loves his brother remains in the light and in him there is no cause for stumbling. But the one who hates his brother is in darkness and he walks in darkness and does not know where he is going, because the darkness has blinded his eyes.