Christians should meet on the sabbath day for church, since this is the day of the "holy convocation" commanded in Leviticus 23:3, and reinforced in many places throughout scripture, including the New Testament. God's people meet on the sabbath day for a "holy convocation," which is a formal assembly of people.
Leviticus 23:3: "Six days shall work be done: but the seventh day is the sabbath of rest, an holy convocation; ye shall do no work therein: it is the sabbath of the LORD in all your dwellings."
The sabbath day begins on what we call Friday, at sunset, and continues until what we call Saturday, at sunset. The children of Israel were commanded to observe the sabbath continually, throughout their generations as a "perpetual covenant."
Exodus 31:16: "Wherefore the children of Israel shall keep the sabbath, to observe the sabbath throughout their generations, for a perpetual covenant."
So the children of Israel, as well as those "grafted in" to Israel, are to remember the sabbath day, to keep it holy, which includes having a "holy convocation" on that day, which is called "church" in the New Testament (meaning "assembly").
Contrary to popular belief, no one in the New Testament ever met for "church" on what we call Sunday. There are two verses that are falsely used to present the idea that Sunday was the day in which they met.
The first is Acts 20:7: "And upon the first day of the week, when the disciples came together to break bread, Paul preached unto them, ready to depart on the morrow; and continued his speech until midnight."
Notice exactly what that verse says, and also what it does not say. It says that the disciples came together to "break bread." They came together to eat. That's not church; that's dinner. And there's no indication that it's referring to the Lord's supper.
Notice too, that it doesn't say that they did that on any kind of regular basis. It does not say, "at the appointed time when the disciples came together every week to break bread," but it merely says they came together on that one instance to eat together, very possibly because it was a big deal to have Paul the apostle with them, and they wanted to be together and with him as much as they could.
Also, notice that when they came together it was either at night or late in the day, since it says Paul preached to them until midnight. The biblical first day of the week starts at sundown on what we call Saturday, and goes until sundown on what we call Sunday. So this dinner meeting took place mostly at night, and either began on what we call Saturday night, after the sabbath day, or they could have started it on Sunday afternoon before sunset. The time of the year was a few days after the Passover feast had ended, since it says in verse 6, "And we sailed away from Philippi after the days of unleavened bread, and came unto them to Troas in five days; where we abode seven days." So the time of the year would have been most likely during what we call April, which would mean that sunset would have been around 7 p.m. or 8 p.m. in Troas. Either way, whether it started on Saturday night or Sunday afternoon, there's no indication that the meeting was considered their weekly meeting for "church," and in fact could not have been, since it began on the first day of the week instead of on the sabbath.
The second verse falsely used to present Sunday as the day for church is 1 Corinthians 16:2: "Upon the first day of the week let every one of you lay by him in store, as God hath prospered him, that there be no gatherings when I come."
Again, pay careful attention to what the verse says, as well as to what it does not say. It says that every one is to "lay by him in store," and the purpose of doing so was so that there would not be any gatherings when Paul came to them. He is telling them to take of their own provisions, probably mostly food items, and gather up a portion to give to Paul so he could take them to needy Christians elsewhere the next time he was in town. If he was talking about money being collected during a church service, why in the world would he say that it needed to be laid up and "stored," and why would he say that it needed to be done ahead of time, "that there be no gatherings when I come," if he was talking about merely gathering a regular collection of money during a church meeting? No, this was a special thing that Paul was telling them to do, on the day after the sabbath, when they were to begin their work week. They were to take of their food and other provisions and lay aside something to give to Christians elsewhere who were in need, and Paul would then be able to easily load it all up once he got to town.
The "Lord's day" is neither Saturday nor Sunday. Those names are of course not used in the Bible (they are pagan), and biblical days always go from sunset to sunset, not midnight to midnight, as do Saturday and Sunday. In Isaiah 58:13 God is speaking, and refers to the sabbath as "my holy day."
Isaiah 58:13: "If thou turn away thy foot from the sabbath, from doing thy pleasure on my holy day; and call the sabbath a delight, the holy of the LORD, honourable; and shalt honour him, not doing thine own ways, nor finding thine own pleasure, nor speaking thine own words:"
The term "the Lord's day" that John uses in Revelation 1:10 is therefore the sabbath day. The beginning of calling Sunday "the Lord's day" was the work of the early Roman Catholic church, and is not at all based on the Bible. The fact that people actually try to use the following verse as proof that Sunday is "the Lord's day" shows that they are suffering from delusion. Nothing whatsoever in the text ties the phrase "the Lord's day" with Sunday, yet they do it anyway.
John 1:10: "I was in the Spirit on the Lord's day, and heard behind me a great voice, as of a trumpet,"
John was obviously doing like every other Christian in the New Testament: obeying the fourth commandment, and remembering the sabbath day to keep it holy. That's when Jesus came to him and showed him all those things in Revelation. Of course John was in exile, and had no other believers with whom he could meet for a holy convocation.
Some also say that God somehow decided to change the day of the week from the sabbath to Sunday because Jesus rose from the dead on Sunday morning, and God wanted to commemorate that event for all time, so he made Sunday a new day to be hallowed, and dropped the sabbath. But there is no indication in the Bible that God changed anything about observance of the sabbath as a result of the resurrection. That viewpoint is entirely an invention of man. Furthermore, Jesus said that he would be three days and three nights in the heart of the earth, which makes a Sunday morning resurrection impossible, since we know he was buried late in the day on the day he was crucified.
Matthew 12:40 "For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth."
We know that people first saw Jesus after his resurrection early in the morning during the first day of the week (our Sunday morning). So the only possible scenario is that Jesus was crucified on Wednesday, and then buried late that day, then spent three days and three nights being buried, and then rose from the dead late in the day Saturday, around the end of the sabbath. Yes, people first saw him early in the morning on the first day of the week, but it's obvious from the time of day that he was buried and the number of days and nights he had to spend "in the heart of the earth" that he had already been risen from the dead for several hours by the time they saw him.
If the only verse of the entire Bible you knew was Mark 16:9, you might think that Jesus rose from the dead Sunday morning instead of late in the day on the sabbath. That verse says, "Now when Jesus was risen early the first day of the week, he appeared first to Mary Magdalene, out of whom he had cast seven devils." Fortunately, we have an entire Bible given to us, and not just one verse. So we know Mark 16:9 is not meant to imply the moment in time when Jesus rose, but rather the moment in time in which he appeared to Mary Magdalene. And again, regardless of the exact moment that Jesus rose from the dead, there is absolutely nothing in the Bible to indicate that God decided to change observance of the sabbath day as a result of the resurrection. Even making a correlation between the two is entirely an invention of man.
The abandonment of remembering the sabbath day to keep it holy, and the adoption of Sunday as a holy day, as well as calling Sunday "The Lord's day" were inventions of the early Roman Catholic church. You must decide whether you will continue to live with that being your authority, or let the Bible be your authority.
Observing the Sabbath and Holy Days Post-Resurrection
Here are a few verses that support observing the weekly sabbath day as well as the biblical holidays, such as Passover, after the resurrection:
Matthew 24:20 "But pray ye that your flight be not in the winter, neither on the sabbath day:" Here, Jesus is telling his disciples about what will happen in the end times, when the abomination of desolation stands in the holy place, and when great tribulation will occur. The implication is that his followers will still be doing what God's people have been doing ever since creation: observing the sabbath day.
Acts 2:1 "And when the day of Pentecost was fully come, they were all with one accord in one place." They were observing Pentecost, which is a holiday that is to be observed fifty days after the weekly sabbath that occurs after the feast of unleavened bread.
Acts 20:6 "And we sailed away from Philippi after the days of unleavened bread, and came unto them to Troas in five days; where we abode seven days." He is obviously still very mindful of the passover feast, and refers to it matter-of-factly, it obviously still being a very real part of their lives.
1 Corinthians 5:8 "Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth." Paul is referring to the feast of passover, also called the feast of unleavened bread, and says we should keep it, being mindful of the spiritual things the feast represents.
Acts 1:12 "Then returned they unto Jerusalem from the mount called Olivet, which is from Jerusalem a sabbath day's journey." Here, he makes a reference to a "sabbath day's journey," which shows that he is obviously still very mindful of the sabbath day and its implications.
Acts 13:42 "And when the Jews were gone out of the synagogue, the Gentiles besought that these words might be preached to them the next sabbath." Acts 13:44 "And the next sabbath day came almost the whole city together to hear the word of God." Paul is preaching on the sabbath day, to both Jews and Gentiles. And there's no indication that he's saying to them, "Let's meet on Sunday next week instead of the sabbath, okay?"
Acts 16:13 "And on the sabbath we went out of the city by a river side, where prayer was wont to be made; and we sat down, and spake unto the women which resorted thither." Notice that he simply refers to "the sabbath," and doesn't say, "what used to be called 'the sabbath' before God changed the day to Sunday!"
Acts 17:2 "And Paul, as his manner was, went in unto them, and three sabbath days reasoned with them out of the scriptures," What was wrong with old Paul? Didn't he know that Sunday was the day for that kind of meeting?
Acts 18:4 "And he reasoned in the synagogue every sabbath, and persuaded the Jews and the Greeks." C'mon Paul, get with the program!
Colossians 2:16-17 "Let no man therefore judge you in meat, or in drink, or in respect of an holyday, or of the new moon, or of the sabbath days: Which are a shadow of things to come; but the body is of Christ." In other words, don't let anyone judge you regarding these things that foreshadow things to come. Notice that he doesn't say that the sabbath "WAS a shadow of things that WERE to come." No, he says those things "ARE" a shadow of things to come, meaning that they are presently serving to foreshadow events that will happen in the future.
1 John 2:6 "He that saith he abideth in him ought himself also so to walk, even as he walked." We know from many references throughout the four gospels that Jesus himself observed the sabbath day as well as the biblical holy days. Never did he say his followers should not also do so, nor did he say that they should stop doing so after he died and was resurrected. If you want to walk as Jesus did, should you not also do this?