41 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. Rest (combined with religious observances) disposes man to forget for a while the business of his everyday life, to turn his thoughts to things heavenly, and to the worship which he so strictly owes to the eternal Godhead. It is this, above all, which is the reason arid motive of Sunday rest; a rest sanctioned by God's great law of the Ancient Covenant-"Remember thou keep holy the Sabbath day,"(31) 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."(32)
Source: Rerum Novarum (Vatican.va)