Thomas Boston, Works, Volume 1, “Of the Providence of God”:
God’s providence is most holy, Psal. cxlv. 17- ‘ The Lord is righteous in all his ways, and holy in all his works.’ Even though providence reach to and be conversant in sinful actions, yet it is pure ; as the sun contracts no defilement, though it shine on a dunghill. For God is neither the physical nor moral cause of the evil of any action, more than he who rides on a lame horse is the cause of his halting. All the evil that is in sinful actions proceeds and flows from the wicked agent, as the stench of the dunghill does not
proceed from the heat of the sun, but from the corrupt matter contained in the dunghill.