佛祖統紀 42.117

42.117

三年。帝召華山隱士陳摶問以飛升黃白之術。對曰。天子以治安天下為務。安用此為。乃遣還山。詔州縣常存問。

In the third year, the Emperor summoned the Huashan hermit Chen Tuan and questioned him regarding the arts of celestial ascension and alchemy. He replied, "The Son of Heaven takes governing the realm in peace as his task; what use is this to you?" He was then sent back to the mountain, and an edict ordered the prefectures and counties to regularly send inquiries and greetings.