The worldly wisdom of the foolish man Is like a sieve, that does alone retain The grosser substance of the worthless bran: But thou, my soul, let thy brave thoughts disdain So coarse a purchase: O be thou a fan To purge the chaff, and keep the winnow'd grain: Make clean thy thoughts, and dress thy mixt desires: Thou art Heav'n's tasker, and thy God requires The purest of thy flow'r, as well as of thy fires.