From the Han-dynasty 《
汉书·
董仲舒传》, itself quoting an older proverb:
临渊羡鱼,
不如退而结网 — 'Standing at the deep pool envying the fish is worse than going back and weaving a net.' Dong Zhongshu (
董仲舒) used it to urge Emperor Wu of Han to stop admiring ancient peace from afar and instead build the institutions that produce it.