We have in Exodus 20:8-11, the Third Commandment in which the Lord instructs Israel to remember the Sabbath and keep it holy. The Commandment is elaborated to explain that just as God had rested after six days of Creation of the world, Israel would also need to rest on the 7th Day. Jesus gave a new definition to rest on the Sabbath by doing the work of compassion. As such, Christians would be obliged to do the work of charity and love towards the neighbor on a Sunday. But in practice, the observance of the Sabbath as a Holy Day is limited to attending the Mass, in so far as many Catholics are concerned.
What does the Catholic Church teach about the observance of Sunday as a Holy Day?