οὐκ ἂν λάβοις παρὰ τοῦ μὴ ἔχοντος → you can't take from one who doesn't have, you can't squeeze blood out of a turnip, you can't get blood out of a turnip, you can't get blood from a stone, you can't get blood out of a stone
-άδος (=χαραμάδα). Ἀπό τό ραγῆναι, ἀπαρ. παθ. ἀόρ. β´ τοῦ ρήγνυμι, ὅπου δές γιά περισσότερα παράγωγα.