Among the forms of shirk (polytheism) is slaughtering an animal for anyone other than Allah. Sacrificing for Allah, seeking closeness to Him, is a type of worship, and Allah has linked this devotion through sacrifice to the act of prayer. He says: “Say, ‘Indeed, my prayer, my rites, my living and my dying are for Allah, Lord of the worlds’” (6:162), and He says: “So pray to your Lord and sacrifice” (108:2). Whoever therefore offers a sacrifice to other than Allah—whether to the jinn, to an occupant of a grave, to a tree, or to a stone, as was the practice of the early pagans—has committed shirk.
The Shaykh singled out sacrifice to the jinn because some Muslims do in fact slaughter for them, believing that the jinn have harmed them and hoping to repel their harm by offering such a sacrifice, or they do so at the bidding of certain superstitious charlatans in search of a cure. Slaughtering for anything other than Allah as an act of devotion is thus a form of shirk in worship, just like praying to other than Allah. Whoever prays at the grave of a prophet, a righteous person, or any other object of veneration, seeking thereby to draw near to something besides Allah, has fallen into shirk.