Leviticus 14:7, 16, 51

He shall sprinkle [the blood] seven times on the one to be cleansed from the leprosy and shall pronounce him [ceremonially] clean. Then he shall let the live bird go free over the open field. [Heb 9:13-15]

and the priest shall dip his right finger in the oil that is in his left palm, and with his finger sprinkle some of the oil seven times before the LORD.

and he shall take the cedar wood and the hyssop and the scarlet string, and the living bird, and dip them in the blood of the slain bird as well as in the running water, and sprinkle the house seven times.