The Mishkan was about to be built. Artisans had received the Spirit of wisdom. Materials were being gathered. And then, in the middle of the construction commands, God paused and spoke about something else entirely: the Sabbath. Targum Pseudo-Jonathan preserves the charge in its expanded form — "Ye shall keep the day of My Sabbaths indeed; for it is a sign between My Word and you, that you may know that I am the Lord who sanctify you" (Exodus 31:13).
Why interrupt the Mishkan to speak of Shabbat?
The sages drew a foundational legal principle from this juxtaposition. The thirty-nine categories of melacha — the creative work forbidden on the Sabbath — were derived from the thirty-nine kinds of labor required to build the Mishkan (Shabbat 49b, c. 500 CE). The Sabbath command was placed inside the construction instructions precisely to say: even for the holiest project imaginable, even to build the house of God, you do not violate the seventh day.
But the targum's addition goes deeper still. The Sabbath is "a sign between My Memra and you." Not simply between God and Israel as abstract parties, but between the speaking-self of God and the listening-self of Israel. The Sabbath is the weekly renewal of the covenant of hearing. On six days Israel does. On the seventh, Israel listens.
And the purpose? "That you may know that I am the Lord who sanctify you." The Sabbath is not only rest. It is the means of knowing. Six days of work teach you your strength. One day of rest teaches you what you could never achieve. In the pause, Israel remembers it was God who made it holy, not its own labor.
The Maggid takes this home: you cannot build a sanctuary seven days a week. Even the holiest project requires the pause that proves the project is not you.