In this sermon titled Blameless in Christ, we find offering a sacrifice on the Sabbath was work.  Yet it was blameless work. Hosea 6:6 For I desired mercy and not sacrifice; and knowledge if God more than burnt offerings.

Jesus spoke of the Sabbath to the Pharisees. They condemned Him because His disciples plucked corn on the Sabbath. Jesus explained that David ate of the showbread in the house of God which was food reserved for the priests alone. Then He mentioned that even the law notes that a priest breaks the Sabbath every time he ministered, but all are blameless.