OET interlinear 3 YHN (3 JHN) 1:11

uW Translation Notes:

Note 1 topic: figures-of-speech / nominaladj

μὴ μιμοῦ τὸ κακὸν, ἀλλὰ τὸ ἀγαθόν

(Some words not found in SR-GNT: Ἀγαπητέ μή μιμοῦ τό κακόν ἀλλά τό ἀγαθόν Ὁ ἀγαθοποιῶν ἐκ τοῦ Θεοῦ ἐστίν ὁ κακοποιῶν οὐχ ἑώρακεν τόν Θεόν)

John is using the adjectives evil and good as nouns in a general sense. Your language may use adjectives in the same way. If not, you could translate these words with an equivalent phrase. Alternate translation: [do not imitate evil things that people do, but imitate good things]

Note 2 topic: figures-of-speech / ellipsis

ἀλλὰ τὸ ἀγαθόν

(Some words not found in SR-GNT: Ἀγαπητέ μή μιμοῦ τό κακόν ἀλλά τό ἀγαθόν Ὁ ἀγαθοποιῶν ἐκ τοῦ Θεοῦ ἐστίν ὁ κακοποιῶν οὐχ ἑώρακεν τόν Θεόν)

John is leaving out some of the words that in many languages a sentence would need in order to be complete. You can supply these words from the context if that would be clearer in your language. Alternate translation: [but imitate the good things that people do]

Note 3 topic: figures-of-speech / metaphor

οὐχ ἑώρακεν τὸν Θεόν

not ˓has˒_seen (Some words not found in SR-GNT: Ἀγαπητέ μή μιμοῦ τό κακόν ἀλλά τό ἀγαθόν Ὁ ἀγαθοποιῶν ἐκ τοῦ Θεοῦ ἐστίν ὁ κακοποιῶν οὐχ ἑώρακεν τόν Θεόν)

John is using the word seen to mean “believed in” or “experienced.” If it would be clearer in your language, you could state the meaning plainly. Alternate translation: [has not experienced God] or [has not believed in God]