EN 1106a13-24 Human virtue is a disposition that makes human become good and perform his function well

ὅ τι μὲν οὖν ἐστὶ τῷ γένει ἡ ἀρετή, εἴρηται. Δεῖ δὲ μὴ μόνον οὕτως εἰπεῖν, ὅτι ἕξις, ἀλλὰ καὶ ποία τις. ῥητέον οὖν ὅτι πᾶσα ἀρετή, οὗ ἂν ᾖ ἀρετή, αὐτό τε εὖ ἔχον ἀποτελεῖ καὶ τὸ ἔργον αὐτοῦ εὖ ἀποδίδωσιν, οἷον ἡ τοῦ ὀφθαλμοῦ ἀρετὴ τόν τε ὀφθαλμὸν σπουδαῖον ποιεῖ καὶ τὸ ἔργον αὐτοῦ· τῇ γὰρ τοῦ ὀφθαλμοῦ ἀρετῇ εὖ ὁρῶμεν. ὁμοίως ἡ τοῦ ἵππου ἀρετὴ ἵππον τε σπουδαῖον ποιεῖ καὶ ἀγαθὸν δραμεῖν καὶ ἐνεγκεῖν τὸν ἐπιβάτην καὶ μεῖναι τοὺς πολεμίους. εἰ δὴ τοῦτ' ἐπὶ πάντων οὕτως ἔχει, καὶ ἡ τοῦ ἀνθρώπου ἀρετὴ εἴη ἂν ἡ ἕξις ἀφ' ἧς ἀγαθὸς ἄνθρωπος γίνεται καὶ ἀφ' ἧς εὖ τὸ ἑαυτοῦ ἔργον ἀποδώσει.