Where does the Bible state that one must worship on Sunday? Where do I find that Jesus rose on Sunday? The Old Testament says that the first day of the week is on Saturday.
Let’s begin with the last statement and then proceed to the two questions. You provided no Biblical reference for your assertion that the Old Testament says that the first day of the week is on Saturday. That is not surprising because there is no such reference or statement. The Sabbath is consistently referred to as the “seventh day.” The seventh day was the day God finished His work; it was the seventh day that God blessed; the seventh day was the day declared to be the Sabbath of the Lord; the seventh day was the day that the Lord blessed and hallowed; the seventh day was the day on which God commanded the Jews to rest; the seventh day was a sign between Israel and God because it was the day on which He rested and was refreshed after the six days of creation. (Gen. 2:2-3; Ex. 20:10-11; 31:15-17.) Other passages could be cited, but this should be sufficient. The first day of the week was not the Sabbath. The seventh day has always been Saturday or its equivalent under the Jewish calendar.
As for the questions, I am assuming that you are not questioning whether God has commanded a day of worship, but whether the commanded day is Sunday or the Lord’s Day or the first day of the week, all three of which refer to the same day. Just as the term “Saturday” is not found in Scripture, neither is the term Sunday. There are references to “the first day of the week” and to “the Lord’s Day.” The passage closest to stating that Jesus rose on the first day of the week is Mark 16:9: “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.” While a number of commentators argue that this establishes the time of the resurrection, The Expositor’s Greek New Testament asserts that it can refer either to the time of the resurrection or the time of the appearance. Whichever it may be, Scripture still establishes that Jesus was raised on the first day of the week. Luke records that Jesus declared that he would rise from the dead “the third day” (Luke 24:46). The disciples to whom Jesus appeared on the road to Emmaus said that “it is now the third day” since Jesus had been crucified” (Luke 24:20-21). Luke identified that third day as the “first day of the week” (Luke 24:1). From that time forward, God’s people observed the first day of the week as their day of worship. Paul gathered with the saints in Troas on the first day of the week (Acts 20:7). He commanded the Corinthians to collect their offering on the first day of the week (1 Cor. 16:2). Early “church fathers” reveal that it was on the first day of the week that Christians worshipped.
Of course, this does not mean that Christians cannot worship on other days, but it was surely the assembly on the first day of the week that the writer of Hebrews said that the Christian was not to forsake (Heb. 10:23-25).
You Must Hear the Gospel
Romans 10:17
You must hear the gospel and then understand and recognize that you are lost without Jesus Christ no matter who you are and no matter what your background is. The Bible tells us that “all have sinned, and come short of the glory of God.” (Romans 3:23) Before you can be saved, you must understand that you are lost and that the only way to be saved is by obedience to the gospel of Jesus Christ. (2 Thessalonians 1:8) Jesus said, “I am the way, the truth, and the life: no man cometh unto the Father, but by me.” (John 14:6) “Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.” (Acts 4:12) "So then faith cometh by hearing, and hearing by the word of God." (Romans 10:17)
You Must Believe
Hebrews 11:6
You must believe and have faith in God because “without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him.” (Hebrews 11:6) But neither belief alone nor faith alone is sufficient to save. (James 2:19; James 2:24; Matthew 7:21)
You Must Repent
Acts 3:19
You must repent of your sins. (Acts 3:19) But repentance alone is not enough. The so-called “Sinner’s Prayer” that you hear so much about today from denominational preachers does not appear anywhere in the Bible. Indeed, nowhere in the Bible was anyone ever told to pray the “Sinner’s Prayer” to be saved. By contrast, there are numerous examples showing that prayer alone does not save. Saul, for example, prayed following his meeting with Jesus on the road to Damascus (Acts 9:11), but Saul was still in his sins when Ananias met him three days later (Acts 22:16). Cornelius prayed to God always, and yet there was something else he needed to do to be saved (Acts 10:2, 6, 33, 48). If prayer alone did not save Saul or Cornelius, prayer alone will not save you. You must obey the gospel. (2 Thess. 1:8)
You Must Confess
Romans 10:9
You must confess that Jesus Christ is the Son of God. (Romans 10:9-10) Note that you do NOT need to make Jesus “Lord of your life.” Why? Because Jesus is already Lord of your life whether or not you have obeyed his gospel. Indeed, we obey him, not to make him Lord, but because he already is Lord. (Acts 2:36) Also, no one in the Bible was ever told to just “accept Jesus as your personal savior.” We must confess that Jesus is the Son of God, but, as with faith and repentance, confession alone does not save. (Matthew 7:21)
You Must Be Baptized
Acts 2:38
Having believed, repented, and confessed that Jesus is the Son of God, you must be baptized for the remission of your sins. (Acts 2:38) It is at this point (and not before) that your sins are forgiven. (Acts 22:16) It is impossible to proclaim the gospel of Jesus Christ without teaching the absolute necessity of baptism for salvation. (Acts 8:35-36; Romans 6:3-4; 1 Peter 3:21) Anyone who responds to the question in Acts 2:37 with an answer that contradicts Acts 2:38 is NOT proclaiming the gospel of Jesus Christ!
You Must Be Faithful Unto Death
Revelation 2:10
Once you are saved, God adds you to his church and writes your name in the Book of Life. (Acts 2:47; Philippians 4:3) To continue in God’s grace, you must continue to serve God faithfully until death. Unless they remain faithful, those who are in God’s grace will fall from grace, and those whose names are in the Book of Life will have their names blotted out of that book. (Revelation 2:10; Revelation 3:5; Galatians 5:4)