So it is that the Gospel has to do with eternal things, but eternal things in the present time. The trouble with people is that they regard eternity as only future, whereas eternity is past, present, and future. It has been, is, and is to be.
The beloved disciple had been banished to the isle of Patmos and while there he had wonderful visions, and this is how he begins the account of them. “I was in the Spirit on the Lord’s day, and heard behind me a great voice.” Revelation 1.10
God is calling the minds of men back to the beginning. He is calling for a return to the Sabbath of the Lord, which a church, spoiled through philosophy and vain deceit, thought to do away with and replace by a day of its own appointment.
There is no reason to believe that the apostles required their converts to keep the first day of the week as a day of rest.
Of course there is not, since there is no hint of such a thing in the New Testament. Yet the Apostle Paul said, “I kept back nothing that was profitable unto you,” and, “I have not shunned to declare unto you all the counsel of God.” Acts 20.20, 27
The terms of your question should be inverted; for it is not Sunday that is called the first day of the week, but the first day of the week that is called Sunday. The number was before the name.
Then when the question is inverted, and it is asked what Bible authority we have for calling the first day of the week Sunday, the reply must be that we have none.
The following questions, “When did they change the Sabbath from the seventh day of the week to the first day? Why did they do so?” were sent to the New York Tribune, by a reader of that journal. The brief answer, which follows, was given in that journal, and is very clear and explicit. We reprint it in hope that it may help others who have similar queries, and stimulate them to further investigation.
When we do not study the Bible for ourselves, we run the risk of forming beliefs based on the traditions and theories of men.
The Bible doctrine of the return of Jesus is one such truth that man has altered to fit his own pet theories.
Without faith it is impossible to please God. The reason for this is that "whatsoever is not of faith is sin" (Romans 14:23), and of course sin cannot please God.
This is why it is that, as stated by the Spirit of Prophecy on the first page of the Review, October 18, 1898, "The knowledge of what the Scripture means when urging upon us the necessity of cultivating faith is more essential than any other knowledge that can be acquired."
Will the Lord receive me?” I reply by another question: Will a man receive that which he has bought? If you go to the store and make a purchase, will you receive the goods when they are delivered?
We are reconciled to God by the death of Christ, and saved by His life. The life, which does this, is the life from which all created things came, and by which they exist. The power of redemption is the power of creation, and that is the power of the life of Christ. The Sabbath is a great memorial of the wonderful works of God, which are the measure of His graciousness. He gave it that we might know that He is the Lord that sanctifies us.