Seven times, to signify the singular use and holiness of it, which it was not only to have in itself, but also to communicate to all the sacrifices laid upon it. The laver, where the priests washed themselves, and the sacrifices, and vessels or instruments of the holy ministration. See Leviticus 6:28.
Related Commentaries of Leviticus 8:11
Leviticus 8:11
11 And he sprinkled thereof upon the altar seven times, and anointed the altar and all his vessels, both the laver and his foot, to sanctify them.