Parallel
Matthew 5:36
Robinson-Pierpont Byzantine Textform · Berean Standard Bible
μήτε ἐν τῇ κεφαλῇ σου ὀμόσῃς, ὅτι οὐ δύνασαι μίαν τρίχα λευκὴν ἢ μέλαιναν ποιῆσαι.
Nor should you swear by your head, for you cannot make a single hair white or black.