 Although a few Christian denominations follow the <unk> practice of observing the Sabbath on Saturday , Catholics , along with most Christians , observe Sunday as a special day , which they call the " Lord 's Day " . This practice dates to the first century , arising from their belief that Jesus rose from the dead on the first day of the week . The <unk> calls on Christians to come together on the Lord 's Day to break bread and give thanks . <unk> is the first to mention Sunday rest : " We , however ( just as tradition has taught us ) , on the day of the Lord 's Resurrection ought to guard not only against kneeling , but every posture and office of <unk> , <unk> even our businesses <unk> we give any place to the devil " ( " De <unk> . " , <unk> ; cf . " Ad nation . " , I , <unk> ; " <unk> . " , <unk> ) . 
