Jesus shows us the point and purpose of holiness in the Jewish law; the recognition of the Holy One.
In fact, the Old Testament itself interprets the law this way. Jesus recalls the story of David who fed his men when they were hungry from the Temple provisions. These were the provisions just for the priests, not to be touched by regular people.
But David, as the anointed and blessed one of God, had the authority to provide for his men out from what was set aside and holy.
If David had this authority to fulfil the needs of justice by using what was set aside and holy, how much more is the Messiah, the incarnate presence of God entitled to act?
As Jesus points out, the Temple priests were exempt from the prohibition of work on the Sabbath because they were in the service and presence of something holier. That is, they went about the work of God in the presence of God. As a result, their ‘work’ was holy and could be done on the day that was set apart to be holy.
Jesus, as the incarnate presence of God, shows us what God’s work is really about. It concerns the merciful provision of something set apart and holy for the needs of his people.
It is, as he says, about mercy and not sacrifice, as he himself will provide the holy sacrifice that will satisfy the justice of the law and the mercy that we desperately need.
The Sabbath was thus made for humanity to recognise and rest in the presence of holiness, which continually provides for our needs out of our great mercy.
So we must remind ourselves that we do our work in a holy appointed time, filled with his provision of holy food (which is meant to signify the Eucharist) and all accompanied and blessed with Jesus’ constant, holy presence.