As Jesus was passing through a field of grain on the sabbath, his disciples began to make a path while picking the heads of grain.
At this the Pharisees said to him, "Look, why are they doing what is unlawful on the sabbath?"
He said to them, "Have you never read what David did when he was in need and he and his companions were hungry?
How he went into the house of God when Abiathar was high priest and ate the bread of offering that only the priests could lawfully eat, and shared it with his companions?"
Then he said to them, "The sabbath was made for man, not man for the sabbath.
That is why the Son of Man is lord even of the sabbath."

Gospel commentary

Leo XIII, Pope from 1878 to 1903
Rerum Novarum, 40-41 (© Libreria Editrice Vaticana)

Life on earth, however good and desirable in itself, is not the final purpose for which man is created; it is only the way and means to that attainment of truth and love of goodness in which the full life of the soul consists. It is the soul, which is made after the image and likeness of God; it is in the soul that sovereignty resides in virtue whereof man is commanded to rule the creatures below him and to use all the earth and the ocean for his profit and advantage. "Fill the earth and subdue it; and rule over the fishes of the sea, and fowl of the air, and all living creatures that move upon the earth"(Gn 1:28) (…) In this respect everyone is equal; there is here no difference between rich and poor, master and servant, ruler and ruled, "for the same is Lord over all"(Rom 10:12).

No one may with impunity outrage that human dignity which God Himself treats with great reverence, nor stand in the way of that higher life which is the preparation of the eternal life of heaven (…).

From this follows the obligation of the cessation from work and labor on Sundays and certain holy days. The rest from labor is not to be understood as mere giving way to idleness; much less must it be an occasion for spending money and for vicious indulgence, as many would have it to be; but it should be rest from labor, hallowed by religion (…). It is this, above all, which is the reason and motive of Sunday rest; a rest sanctioned by God's great law of the Ancient Covenant-"Remember thou keep holy the Sabbath day,"(Ex 20:8) and taught to the world by His own mysterious "rest" after the creation of man: "He rested on the seventh day from all His work which He had done"(Gn 2:2).