瑜伽師地論略纂 9.78

9.78

論云「終不妄計世瑞吉祥以為清淨」者，第十、明不妄計，唯知佛為清淨也。　世瑞吉祥者，謂世人妄計世瑞相，如欲行時見淨水香華，是行時瑞相；又計吉祥，即隨見此瑞法號為吉祥。今不如是。

Where the treatise says, "One never falsely grasps mundane omens and auspicious signs as purity": this is the tenth, clarifying that one does not falsely grasp, knowing only the Buddha to be purity.
'Mundane omens and auspicious signs' means that worldly people falsely grasp mundane auspicious portents, such as seeing pure water, incense, and flowers when about to travel as an auspicious omen for travel; furthermore, grasping auspiciousness means that following whatever omen one sees, one terms it auspicious. Now, it is not like that.