From Yang Xiong's 《
剧秦美新》 (Han dynasty):
懿律嘉量，
金科玉条 ('fine laws and good measures, golden articles and jade clauses').
科 originally meant a clause of statute law,
律 a code of regulations — calling them
金 (gold) and
玉 (jade) is the highest praise. Modern usage often carries a slightly skeptical tone, as in 'don't treat X as gospel'.
