But the seventh day is the sabbath of the LORD thy God:
Exodus 20:10
"Several of the early fathers wrote in opposition to the observance of the seventh day.
We now give the reasons assigned by each for that opposition. The writer called Barnabas did not keep the seventh day, not because it was a ceremonial ordinance unworthy of being observed by a Christian, but because it was so pure an institution that even Christians cannot truly sanctify it till they are made immortal. Here are his words:
"Attend, my children, to the meaning of this expression, `He finished in six days.' This implieth that the Lord will finish all things in six thousand years, for a day is with him a
thousand years. And he himself testifieth, saying, `Behold, to-day will be as a thousand years.' Therefore, my children, in six days, that is, in six thousand years, all things will be finished. `And he rested on the seventh day.' This meaneth: When his Son, coming [again], shall destroy the time of the wicked man, and judge the ungodly, and change the sun, and the moon, and the stars, then shall he truly rest on the seventh day. Moreover, he says, `Thou shalt sanctify it with pure hands and a pure heart.' If, therefore, any one can now sanctify the day which God hath sanctified, except he is pure in heart in all things, we are deceived. Behold, therefore: certainly then one properly resting sanctifies it, when we ourselves, having received the promise, wickedness no longer existing, and all things having been made new by the Lord, shall be able to work righteousness. Then we shall be able to sanctify it, having been first sanctified ourselves. Further he says to them, `Your new moons and your sabbaths I cannot endure.' Ye perceive how he speaks: Your present sabbaths are not acceptable to me, but that is which I have made [namely this], when giving rest to all things, I shall make a beginning of the eighth day, that is, a beginning of another world, wherefore, also, we keep the eighth day with joyfulness, the day, also, on which Jesus rose again from the dead."
Observe the points embodied in this statement of doctrine:
1. He asserts that the six days of creation prefigure the six thousand years which our world shall endure in its present state of wickedness. 2. He teaches that at the end of that period Christ shall come again 
and make an end of wickedness, and "then shall he truly rest on the seventh day."
3. That no "one can now sanctify the day which God hath sanctified, except he is pure in heart in all things."
4. But that cannot be the case until the present world shall pass away, "when we ourselves, having received the promise, wickedness no longer existing, and all things having been made new by the Lord, shall be able to work righteousness. Then we shall be able to sanctify it, having been first sanctified ourselves." Men cannot, therefore, keep the Sabbath while this wicked word lasts.
5. Therefore, he says, "Your present sabbaths are not acceptable," not because they are not pure, but because you are not now able to keep them as purely as their nature demands.
6. That is to say, the keeping of the day which God has sanctified is not possible in such a wicked world as this.
7. But though the seventh day cannot now be kept, the eighth day can be, and ought to be, because when the seven thousand years are past, there will be at the beginning of the eighth thousand, the new creation.
8. Therefore, he did not attempt to keep the seventh day, which God had sanctified; for that is too pure to be kept in the present wicked world, and can only be kept after the Savior comes at the commencement of the seventh thousand years; but he kept the eighth day, with joyfulness on which Jesus arose from the dead.
9. So it appears that the eighth day which God never sanctified, is exactly suitable for observance in our world during its present state of wickedness.
10. But when all things have been made new, and we are able to work righteousness, and wickedness no longer exists, then we shall be able to sanctify the seventh day, having first been sanctified ourselves.
The reason of Barnabas for not observing the Sabbath of the Lord is not that the commandment enjoining it is abolished, but that the institution is so pure that men in their present imperfect state cannot acceptably sanctify it.
--They will keep it, however, in the new creation, but in the meantime they keep with joyfulness the eighth day, which having never been sanctified by God is not difficult to keep in the present state of wickedness."
J.N. Andrews