Aristotle,
Rhetoric 1.1.7 (1354 a 31; tr. J.H. Freese):
It is proper that laws, properly enacted, should themselves define the issue of
all cases as far as possible, and leave as little as possible to the discretion of the
judges.
μάλιστα μὲν οὖν προσήκει τοὺς ὀρθῶς κειμένους νόμους, ὅσα ἐνδέχεται, πάντα
διορίζειν αὐτούς, καὶ ὅτι ἐλάχιστα καταλείπειν ἐπὶ τοῖς κρίνουσι.
The same (tr. C.D.C. Reeve):
Above all, though, it is fitting for laws that are correctly laid down to
define everything themselves, wherever possible, and leave the fewest
things up to the jurors.