This should be considered a Catholic Response.
Should Jewish Christians not work on Saturday or Sunday? I feel that if you can manage your life to allow time for the day of rest then you have been given an advantage. For projects and work take away from family time and rest. That being said there are exceptions, and there are also ones feeling of guilt.
So let us look to why there was a commandment for the Sabbath. The Jews were being treated as slaves, and (I take a logical guess here) where probably forced to work every day.
I am the Lord your God, who brought you out of the land of Egypt, out of the house of bondage.
So let us look at this reasonably. If God decided to do the "work" involved in freeing the slaves, what benefit do they receive if they are continued to work as they where forced to do previously?
So that was purpose, let us see from the viewpoint of function. In function the rest is to give peace, rest, and the rebuilding of the bodies. So a problem started to rise within the observance of the day. Not about the observance of the day, but how the day was observed.
Psalm 95:7-11 NKJV
For He is our God, And we are the people of His pasture, And the sheep of His hand. Today, if you will hear His voice: 8 “Do not harden your hearts, as in the rebellion, As in the day of trial in the wilderness, 9 When your fathers tested Me; They tried Me, though they saw My work. 10 For forty years I was grieved with that generation, And said, ‘It is a people who go astray in their hearts, And they do not know My ways.’ 11 So I swore in My wrath, ‘They shall not enter My rest.’”
So we can clearly see that how the heart would receive his word, is an important part of observing this commandment. Now logically what is more important? To observe the day with the right heart? Or, to observe the day with the wrong heart? Now if to observe the day with the hardened heart God swore the he would not let the entrance into rest. I choose that observing the day with the good heart is the right choice.
Defining work is important: for what is done out of love, may not be considered work. Things done for money usually are considered work. Yet if that money is for the family, and not for selfish gain, that may also not be considered work. Yet this is from a perspective of conscience. For a radiant attitude can be drawn to scorn when guilt weighs on the mind.
Notice that the rest was taken away with the word "Today".
Psalm 95:7b NKJV
...Today, if you will hear His voice
Therefore, we can reason that if the Good Heart is today, then rest can occur today as well!
For if Joshua had given them rest, then He would not afterward have spoken of another day. 9 There remains therefore a rest for the people of God. 10 For he who has entered His rest has himself also ceased from his works as God did from His. 11 Let us therefore be diligent to enter that rest, lest anyone fall according to the same example of disobedience.
Now if one enters into the rest "Today" and "Today" occurs "Everyday". Then "Today" also occurs on the "Sabbath". Yet I do also try to treat the Shabbat special, as a time for family and rest.
During the Ecumenical councilat Nicaea Constantine was in a position to create peace and he took it. The original reason for the 1st day of the week - which we call Sunday in English was this:
Some observed shabbat, and did not want to do work on the Saturday. So they where asked to gather on the first day of the week for money collections.
1 Corinthians 16:2 NKJV
On the first day of the week let each one of you lay something aside, storing up as he may prosper, that there be no collections when I come.
When they where gathered, some would eat and get drunk, while others where put to shame.
1 Corinthians 11:22 NKJV
What! Do you not have houses to eat and drink in? Or do you despise the church of God and shame those who have nothing? What shall I say to you? Shall I praise you in this? I do not praise you.
Therefore there was a call to order.
1 Corinthians 14:33 NKJV
For God is not the author of confusion but of peace, as in all the churches of the saints.
And a request that all join in the Lord's Supper.
1 Corinthians 11:20 NKJV
Therefore when you come together in one place, it is not to eat the Lord’s Supper.
Since the church members were to be poor. They could fulfill the sacraments.
Leviticus 5:13 NKJV
...The rest shall be the priest’s as a grain offering.
For burnt offerings part of were no longer needed for Leviticus 5:11-13.
Isaiah 1:11 NKJV
To what purpose is the multitude of your sacrifices to Me?” Says the Lord. “I have had enough of burnt offerings of rams And the fat of fed cattle. I do not delight in the blood of bulls, Or of lambs or goats.
Personally I suggest you take the day. Yet if "Father God" is in need of your body. How can he hold it against you if you do his will? For God is not hypocritical. Yet all things are simplified to love the one next to you as yourself. Also I find that family house work on Sunday provides its own rest in the afternoon. As I have the time to write this for you because of this.
I choose to rest on Saturday, then take service on Sunday at 8 AM at the Catholic Church for the sacrifice, then 10:30 AM at the Assemblies of God for fellowship and praise. Yet each has their own way, and I don't always get to play out my routine. Family trips sometimes gets me driving on Saturday, and I do admit I sometimes load the car, when I could prepare that on Fridays, or unload when we arrive. I feel however that deeds done for family environmental settings for the comfort of my family, or to reduce family anxiety possibilities, all fall within Loving the ones next to me. God has not killed me yet, and if I do these things in error, then I will learn them from him. As of yet however, my heart does not condemn me, and though ignorance is not an excuse. In this I do not believe that I error, that does not mean that I do not. Yet the Lord is merciful, and I am grateful.