As part of the Day of Atonement, the Lord wanted Aaron to kill a bull, and,

“He shall take some of the blood of the bull and sprinkle it with his finger on the mercy seat on the east side; and before the mercy seat he shall sprinkle some of the blood with his finger seven times” (Leviticus 16.14).

Seven times was enough to get done what the Lord wanted done, and for that, He would forgive the people of their sins, although we know that the blood of bulls could not take away sins, but this was all done, looking forward to the sacrifice of the Son of God.

Forgiveness takes place in the heart of God, and when man does what God says, He can forgive.