Moses then convoked the whole Israelite community and said to them…
On six days work may be done, but on the seventh day you shall have a sabbath of complete rest, holy to the Lord…
Take from among you gifts to the Lord; everyone whose heart so moves him shall bring them—gifts for the Lord
The reason the Sabbath is mentioned first before the construction of the Tabernacle is that the construction of the Tabernacle connected the heart of every person in Israel to one another without even a hint of ego.
Initially, each skilled craftsperson made his or her specialized contribution, and it was apparent that every piece was truly remarkable. Afterwards, when all the individual twists and ties were joined together, they saw how each thing fit perfectly, as if it was all made by one person. They realized that everything they had done was not because of/for themselves – it was only the hand of God guiding their handiwork, and this is why there was a perfection of form in the completed building. How is it possible to feel superior over another when it was made only with the help of God?
The Talmud (BT Megillah 9a) relates the story of King Ptolemy gathering the 72 elders [to translate the Torah into Greek, independent of one another] who all acted as one mind and made the same emendations to the biblical text. It seemed to each one that he had uncovered a profound and deep wisdom in his changes. When it was revealed that they had unearthed the exact same insights, they understood it all had been God’s will.
This is why the Sabbath is placed in relation to the building of the Tabernacle, for the essential principle that connects them is the commandment of the Sabbath. The Sabbath underlies any commandment done with the intention of being for the sake of Heaven, as this intention is called “Sabbath.”
So too with the construction of the Tabernacle. All their work was to glorify Heaven to allow the Divine Presence to dwell with Israel. It was this that joined their hearts together, for the Divine Presence would not reside there if even one peg or rod is missing. Therefore, it wasn’t possible to feel superior to another at all, even the one who constructed the Holy Ark compared to the one who made the pegs of the outer courtyard, as it says in the Talmud (BT Sotah 40a), “What do you care? Through this and this the Most High is praised!”
And this is Moses then convoked the whole Israelite community.