The Five Books Against Marcion by Tertullian
Chapter XXI.--The Law of the Sabbath-Day Explained. The Eight Days' Procession Around Jericho. The Gathering of Sticks a Violation.
Similarly on other points also, you reproach Him with fickleness and instability for contradictions in His commandments, such as that He forbade work to be done on Sabbath-days, and yet at the siege of Jericho ordered the ark to be carried round the walls during eight days; in other words, of course, actually on a Sabbath. You do not, however, consider the law of the Sabbath: they are human works, not divine, which it prohibits. For it says, |Six days shalt thou labour, and do all thy work; but the seventh day is the Sabbath of the Lord thy God: in it thou shalt not do any work.| What work? Of course your own. The conclusion is, that from the Sabbath-day He removes those works which He had before enjoined for the six days, that is, your own works; in other words, human works of daily life. Now, the carrying around of the ark is evidently not an ordinary daily duty, nor yet a human one; but a rare and a sacred work, and, as being then ordered by the direct precept of God, a divine one. And I might fully explain what this signified, were it not a tedious process to open out the forms of all the Creator's proofs, which you would, moreover, probably refuse to allow. It is more to the point, if you be confuted on plain matters by the simplicity of truth rather than curious reasoning. Thus, in the present instance, there is a clear distinction respecting the Sabbath's prohibition of human labours, not divine ones. Accordingly, the man who went and gathered sticks on the Sabbath-day was punished with death. For it was his own work which he did; and this the law forbade. They, however, who on the Sabbath carried the ark round Jericho, did it with impunity. For it was not their own work, but God's, which they executed, and that too, from His express commandment.