Leviticus 4:6

When the anointed priest sinned, he ministered the blood himself. Unlike other sacrifices where blood was sprinkled on the altar in the court, the high priest’s sin offering blood was carried into the sanctuary. This reflected the greater seriousness of his sin.

The priest dipped his finger in the blood and sprinkled it seven times before the veil, “before the Lord,” and put some on the horns of the altar of incense (v. 7).

The blood was sprinkled before, not on, the veil. Only one finger was used. This sprinkling was done only when the anointed priest or the whole congregation sinned. The frequency of such sin offerings is unknown but probably rare.

The sprinkling related to the law behind the veil, but the blood did not reach the law because the veil intervened. Facing the law was reserved for the Day of Atonement, the day of judgment for Israel (Hebrews 10:19-20).