Keep holy the Lord's Day
When we consider the sin of Adam and Eve, one of the first things that becomes obvious is that our First Parents had absolutely nothing of value that they could offer to God in reparation for their sin. Even if they had the possessions of the greatest kings, these would have been of no real interest to the Almighty God. And, in any event, anything and everything that they had already belonged to God, who made all things and is depended upon to keep them in existence.
But in spite of this utter poverty, God encouraged mankind to offer sacrifices in worship and in reparation for sin. God was willing to accept our offerings, not because they were of great value to Him, but because He recognized that they represented substantial efforts on our part. In this way, God is sort of like the Parent who is pleased to receive a gift from a young son or daughter; not because the gift is very valuable, but because it represents the efforts and the love of the child for those who love him. (Those of you who are parents know what I am talking about; with the ash trays, and the finger paintings, and the tie clips, and the what not that came back from school or from summer camp!)
In the Old Testament we read about God's people offering Him a variety of sacrifices, ranging from cattle and lambs and goats, through pigeons, on to hot loaves of bread that were continuously set before God in the tabernacle. To a desert people like the Jews these things were of great value because they represented a great deal of work in cultivation and husbandry. They represented something of God's favor, because a poor harvest or pestilence among the flock might make them unavailable. They represented life itself because in lean years they might substantially cut into the food supply.
The sacrifice of the New Testament follows similar lines. Our priests offer small wafers of unleavened bread and a little drink of wine in a golden cup; perhaps just a few cents worth of materials, just a token representation of our possessions and our industry. But, of course, the real value in the Sacrifice of the New Testament comes when the priest utters the words of Christ over these offerings; when through the power of Christ and in the person of Christ, he can hold up that Host and that Chalice, and truthfully say to God the Father "This is My Body. This is My Blood" -- and be offering to Him not something from the dinner table, but rather, offering Him His only-begotten Son. Instead of offering Him the poor gifts of mankind, Catholics thus offer God the only all-perfect gift.
There is another sacrifice that God demands of His people; both those of the Old and the New Testament. That is the sacrifice of keeping holy the Day of the Lord; a sacrifice of our time, if you will. And here again, man is giving back something to God that he got from God in the first place, just like the cattle, or the bread and wine, or our crucified Lord. There would be no such thing as time if God had not created the material universe; there would be no Sabbath Day if God had not sanctified the Week of Creation; there would be no Sunday if God had not risen from the dead on the day after the seventh day. And God considers this sacrifice of our time so important that He orders it in His Ten Commandments.
God isn't asking a lot from us. (Some joke that He is doing nothing more than keeping the greedy from working themselves to death.) At a minimum, we must attend Mass on the Sundays and Holy Days of obligation throughout the year -- but even the Holy Days have been greatly reduced in number so that today we are required to observe only six of them. Hopefully, we will do more than just show up at Mass; that we will also go to Confession and Communion, perhaps we'll arrive early enough to join in the Rosary, or we'll make a practice of spending Sunday afternoon reading something spiritual.
God doesn't demand the impossible from us, or even the terribly inconvenient -- that is the message of today's Gospel -- the Sabbath is not intended to hurt people, but rather to refresh them and draw them closer to God. As our Lord says elsewhere, Man was not made for the Sabbath, but rather, the Sabbath was made for man. So, on those days when transportation problems, or the need to care for the sick or the elderly or the young, or some other urgent matter keeps us from attending Mass, we do not sin by staying home.
God also demands that we refrain from unnecessary servile work on Sundays and Holy Days. The shopping and the grass cutting and the house painting and the laundry ought to happen some other time. Here again, following our Lord's example, there are obviously exceptions -- for some work must be performed on Sundays. And most folks recognize that work for the Church, or truly charitable works performed for those in need do not violate the spirit of the Sabbath.
In all of these things, we ought to be careful not to give scandal or cause others to violate the observance of Sunday. Stopping to buy a quart of milk at the grocery store may not seem like a grave violation, but it is just one more action that says, "God's laws are not very important," and one more reason for the store owners to keep that store open all Sunday long.
Now, let me suggest one more thing that goes beyond the "letter of the law." That is that we ought to have a certain generosity in all the aspects of our spiritual life. As we have seen, we have nothing to give God except for what He has previously given us -- in reality our gift is more a gift of love or good intention. So we might consider doing a little bit more than what is strictly required of us. For example, the letter of the law tells us that we don't have to make up a missed Mass on Monday or Tuesday or whenever -- but God might appreciate that all the more -- almost as much as He would appreciate your being at Mass on a day when you have no reason at all for being there.
Remember: God has given us His only-begotten Son -- the least we can do is to give Him back a little bit of our time.