Listen now | From the audiobook Explanation of Catholic Morals - Chapter 53 clarifies that while servile works are generally prohibited on the Lord's Day, exceptions exist based on the principle that "the Sabbath was made for man, not man for the Sabbath." These lawful exceptions include works necessary for divine worship's preparation or solemnity, acts of charity towards those in distress, and both public and personal necessities (e.g., wartime efforts, preventing serious loss, or unavoidable occupational demands for individuals who cannot secure comparable employment without Sunday labor). However, individuals working out of necessity should still regret the circumstance and strive for a more spiritually favorable situation. The chapter concludes by defining a "notable time" of servile work (approximately two hours) as a mortal sin if performed without sufficient reason, indicating that the gravity of the offense increases with the duration and deliberateness of the prohibited labor.