Answer: The sabbath or Lord's day is to be sanctified by an holy resting all the day, not only from such works as are at all times sinful, but even from such worldly employments and recreations as are on other days lawful; and making it our delight to spend the whole time (except so much of it as is to betaken up in works of necessity and mercy) in the public and private exercises of God's worship: and, to that end, we are to prepare our hearts, and with such foresight, diligence, and moderation, to dispose and seasonably dispatch our worldly business, that we may be the more free and fit for the duties of that day.
- Westminster Larger Catechism
At a former church, it was our practice all to go to lunch together after Sunday worship. It was a very small church, only about a dozen members, and we were widely dispersed, so participation was necessary if I were to have any sort of relationships with my brethren. Doing that caused me great discomfort of conscience, because I believe that a Christian should avoid commercial activity on the Lord's Day. As the IVth Commandment says, we are not only to rest from our own labors, but also to relieve our servants of theirs. I am glad to say that my current situation doesn't put me in that conflict.
Some excuse eating out on Sundays as giving the wife the opportunity to rest. I think that is a good concern. However, I cannot accept that one person honors the Day by putting the work off on someone else.
Consider the Commandment itself (Exodus 20:10), "the seventh day is a Sabbath to the Lord your God. On it you shall not do any work, you, or your son, or your daughter, your male servant, or your female servant, or your livestock, or the sojourner who is within your gates." It is forbidden even to put the labor off onto one's employees or animals. I have seen this described as the first labor legislation.
Nehemiah expands this even further. Nehemiah 10:31 tells us, "if the peoples of the land bring in goods or any grain on the Sabbath day to sell, we will not buy from them on the Sabbath or on a holy day. And we will forego the crops of the seventh year and the exaction of every debt." And Neh. 13:15, "In those days I saw in Judah people treading winepresses on the Sabbath, and bringing in heaps of grain and loading them on donkeys, and also wine, grapes, figs, and all kinds of loads, which they brought into Jerusalem on the Sabbath day. And I warned them on the day when they sold food." Both of these verses describe people who willingly profit from providing Lord's Day labor to resting believers. Yet, this voluntary labor is still forbidden. And this is exactly what is happening when believers "honor" the Lord's Day by going to commercial establishments, where others profit from violating the Fourth Commandment.
Where I live, restaurants are swamped on Sunday afternoons. I sincerely believe that this grieves the Lord.