Hezekiah addresses, not the priests, but the congregation: “Now that by the atoning sacrifice which has been offered for you, you are consecrated once more to be a holy people to the Lord, approach with confidence and offer your free-will offerings as of old.”
Burnt offerings - The term thus translated is applied especially to those victims which were to be wholly consumed upon the altar. In the “sacrifices,” or peace offerings generally, and the “thank offerings” - a particular kind of peace offering Leviticus 7:12) - the greater part of the victim belonged to, and was consumed by, the worshipper. Hence, to offer “burnt offerings,” was indicative of a “free heart.”