Exodus 31:12

“And the Lord spake unto Moses, etc.] After he had described to him the place of worship, and appointed the priests that should minister in it, and ordered the making of all things appertaining to it, and the workmen that should be concerned therein, he repeats the law of the sabbath, and puts in mind of the time of worship: saying: as follows.”

“Verily my sabbaths ye shall keep--The reason for the fresh inculcation of the fourth commandment at this particular period was, that the great ardor and eagerness, with which all classes betook themselves to the construction of the tabernacle, exposed them to the temptation of encroaching on the sanctity of the appointed day of rest. They might suppose that the erection of the tabernacle was a sacred work, and that it would be a high merit, an acceptable tribute, to prosecute the undertaking without the interruption of a day's repose; and therefore the caution here given, at the commencement of the undertaking, was a seasonable admonition.”

“The penal law of the Sabbath. Exodus 35:2-3. In the fourth commandment the injunction to observe the seventh day is addressed to the conscience of the people (see Exodus 20:8 note): in this place, the object is to declare an infraction of the commandment to be a capital offence. The two passages stand in a relation to each other similar to that between Leviticus 18:0, Leviticus 19:0, and Leviticus 20:0. It seems likely that the penal edict was especially introduced as a caution in reference to the construction of the tabernacle, lest the people, in their zeal to carry on the work, should be tempted to break the divine law for the observance of the day. Exodus 31:14 See Numbers 15:32-36. The…”

“31:12-18 The Sabbath was understood to be the unique sign of the covenant (31:13, 16, 17; see also 20:8-11; Isa 58:13-14; Jer 17:21-27; Neh 13:15-22). The Sabbath is also said to figure significantly in the achievement of God’s underlying purpose of making his people holy, that is, set apart for his exclusive use and sharing his character (Exod 31:13, 14, 15). Resting from their own work (31:15, 17) was also a practical way of demonstrating genuine dependence on God to meet their needs (see 20:8-11 and study notes).”

“(cf. Exo 35:2-3). God concludes by enforcing the observance of His Sabbaths in the most solemn manner, repeating the threat of death and extermination in the case of every transgressor. The repetition and further development of this command, which was included already in the decalogue, is quite in its proper place here, inasmuch as the thought might easily have occurred, that it was allowable to omit the keeping of the Sabbath, when the execution of so great a work in honour of Jehovah had been commanded. "My Sabbaths:" by these we are to understand the weekly Sabbaths, not the other sabbatical festivals, since the words which follow apply to the weekly Sabbath alone. This was "a sign…”