It is true that the Corinthians were commanded to take up a collection for the poor saints of Judea on the first day (1Corinthians 16:2). If Sunday was the new day of rest, however, Paul would have never asked the Corinthians to engage in all the labor needed to gather food, fruits, etc. for the believers in Jerusalem. He would have told them to do such work on the other days of the week.
There are at least SIX major reasons why God's rest on the seventh day should be kept today.
A special creation
The Sabbath was instituted by God's own example on the seventh day of creation week:
"Thus the heavens and the earth, and all the host of them, were finished. And on the seventh day God ended His work which He had done, and He rested on the seventh day from all His work which He had done. Then God blessed the seventh day and sanctified it, because in it He rested from all His work which God had created and made." (Genesis 2:2-3, NKJV throughout).
The God of the universe chose to cease from His labor, not because He was tired (Isaiah 40:28), but because He wanted to set an example for all mankind. He specifically blessed and made holy the seventh day, a day of ceasing, over 2,000 years before the time of Moses and the Old Covenant. Exodus 20 corroborates this fact:
"For in six days the Lord made the heavens and the earth, the sea, and all that is in them, and rested the seventh day. Therefore the Lord blessed the Sabbath day and hallowed it." (Exodus 20:11)
The seventh day rest was not a mere Mosaic statute given only to Israel under the Old Covenant. It was set apart at the beginning, as a memorial of God's creative power. An interesting footnote to the early origin of the God's rest is that in over one hundred languages the name for the seventh day of the week is a variation of the word Sabbath.
The Ten Commandments
When asking a Sabbathkeeper why he keeps the Sabbath, he will likely respond "For the same reason I honor my parents"! It is an irrefutable answer because both God's rest and honoring parents are required by the same set of laws. It is a rare Christian who will speak negatively toward this law, even though most ignore the Fourth Commandment, which states:
"Remember the Sabbath day, to keep it holy. Six days you shall labor and do all your work, but the seventh day is the Sabbath of the Lord your God . . . " (Exodus 20:8-10).
God stressed the importance of the Ten Commandments when he gave them with His own voice and inscribed them in stone with His own finger. He must have chosen very carefully the ten spiritual precepts to be included in this law, which was to serve as a constitution of sorts for the nation of Israel. These were not new laws, for actions such as murder, lying, and adultery are all condemned from the beginning (Genesis 4:8-16; 20:3-6; 39:9).
In the New Testament, the Ten Commandments are consistently upheld as reflecting God's will for mankind. Jesus reinforced the Ten Commandments (Mark 10:17-19). So did Paul and James (Romans 2:13, 21; 7:7-14, 21; James 2:8-12). The Ten Commandments continue to stand as God's will for all mankind.
Jesus kept it and taught it
Throughout His earthly ministry, Jesus observed the fourth commandment. Luke records:
"So He came to Nazareth, where He had been brought up. And as His custom was, He went into the synagogue on the Sabbath day, and stood up to read." (Luke 4:16).
On many occasions, Jesus incurred the wrath of the Pharisees because He did not live according to their humanly devised regulations. He healed on the day of rest, allowed His disciples to shell out kernels of grain to eat, and told a man to pick up his bedroll. This was all contrary to the Pharisees' traditions but never once did He speak negatively about the commandment itself. He observed it and showed how it should be kept. He even proclaimed Himself Lord of God's rest.
"And He said to them, '. . . Therefore the Son of Man is also Lord of the Sabbath.'" (Mark 2:27-28).
Jesus was indeed Lord of the Biblical day of rest. He was there in the beginning with God in creating it (John 1:3; Ephesians 3:9). He showed by His example how it was to be kept as a blessing for mankind, as a day of freedom and delight. He showed that doing good, taking care of animals, handling emergencies, shelling out grain to eat, were all permissible on this day of rest (Matthew 12:11-12; Luke 14:5). He objected to the petty traditions of men that turned the Sabbath into a burden, but He upheld the rejuvenation and freedom enjoined by the Fourth Commandment (Mark 3:1-5; Luke 13:11-17).
In prophesying the destruction that was to come on Jerusalem in A.D. 70, Jesus told His followers,
"And pray that your flight may not be in winter or on the Sabbath." (Matthew 24:20).
If the fourth commandment was to be nullified by His death, Jesus' statement makes no sense at all. On the other hand, His statement indicates that seventh day would continue as a holy day for God's people. Hence, an emergency flight, while not strictly prohibited, would not be in keeping with God's purpose for this day of rest. Throughout His ministry, Jesus affirmed the Sabbath.
Fourth commandment taught and followed by early church
Following Jesus' death, His most intimate followers continued to observe God's day of rest. Contrary to popular belief, there is no evidence that they abandoned the seventh day of the week for the first day. While Jesus lay in the tomb, the women prepared spices for His body and then:
"And the women who had come with Him from Galilee followed after, and they observed the tomb and how His body was laid. Then they returned and prepared spices and fragrant oils. And they rested on the Sabbath according to the commandment." (Luke 23:55-56).
The important fact about these verses is that Luke, a Gentile writing to a Gentile, wrote this account several decades after the event. He in no way qualified the commandment the women obeyed as being "old," or "Jewish" or "done away." It was still, simply, "the commandment." Paul consistently used the Sabbath for teaching both Jews and Gentiles "as his custom was" (Acts 17:2).
In Pisidia Paul and Barnabas went into the synagogue where they were asked to speak (Acts 13:14-15). When they had finished, some of the listeners asked them to return in a week.
"On the next Sabbath almost the whole city came together to hear the word of God " (Acts 13:44).
Had the Christians been observing Sunday, they could easily have met the next day after this first meeting. The first day of the week, however, was a day of work. Apparently, both Jews and Gentiles, even "the whole city," were oriented to the seventh-day Sabbath. Acts 18:3-4 describes Paul's stay in Corinth, where he worked as a tentmaker during the week. When did he rest from his physical labor to teach Jews and Greeks? Paul rested on a Saturday, not on Sunday.
Sunday worship adopted for non-Biblical reasons
History reveals that it was because of political and social pressures that the seventh day was gradually abandoned for Sunday - long after the time of the Apostles. Severe anti-Jewish attitudes developed in the Roman world during the first and second centuries. As acts of repression, the Romans outlawed circumcision, sacrificing, Sabbathkeeping and other Jewish practices. Consequently, Christians, particularly at Rome, found it expedient to put as much distance as possible between themselves and the Jews, to demonstrate to the Romans that they were not Jewish. One way they did this was to work on the Sabbath. Sunday, which was already used by many Romans as a holiday, was a convenient substitute.
When Constantine officially recognized Christianity in the fourth century, he put the power of the Roman empire behind Sunday observance. In the centuries that followed, the first day of the week became firmly entrenched as the church's day of rest such that even Protestant reformers could not dislodge it, though they claimed their authority from the Bible and Bible only. Sunday observance was adopted for the sake of political expedience and is based solely on church tradition.
Man NEEDS to Rest
Each week we need time to recuperate from the physical, mental, and emotional pressures of life. We need time to contemplate God's creation, His love, and our need for His redemptive powers. God, in His wisdom, set aside at Creation a day just for those purposes. Wise men have come to see that they get more done in six days if they rest on the seventh. The Sabbath is not merely an Old Covenant legal requirement, but a New Covenant day of liberty from stress and toil. it is a day when we are free to rest, free to do good, free to be rejuvenated, free to worship and fellowship with others.