“On the first day” – Rabbi Shmuel bar Abba said: What is “the first day”? Since the first day that the Holy One blessed be He created the world, He desired to dwell with His creations in the lower worlds. See what is written regarding the creation of the first day: “It was evening; it was morning, one day” (Genesis 1:5). “The first day” is not written, but rather “one day.”
Just as the verse says “one day,” the verse could have said “two days,” “three days”? Rather, why did the verse say “one day”?29The first day is described as "one day", not the first day, whereas the other days are called the second day, the third day etc. It is that, since the Holy One blessed be He was alone in the world, He desired to dwell with His creations in the lower worlds. He did not do so.30Thus, day one of creation was not the first day that God dwelled in the world.
To indicate this, the word first was not used until the Tabernacle was erected. It was only when the Tabernacle was erected, and the Holy One blessed be He rested His Divine Presence in it, and the princes came to present, that the Holy One blessed be He said: ‘Let it be written that on this day the world was created.’ Another matter, “on the first day” – it does not say “on the day the Tabernacle was erected” here, but rather, “on the first day.”
What is “the first”? It is the first in terms of the creation of the world. It teaches that it was Sunday. Consequently, that day took ten crowns: First in terms of creation of the world; first for priesthood; first for princedom; first for the Divine Presence; as it is stated: “they shall craft a sanctuary for Me and I will dwell in their midst” (Exodus 25:8); first for service; first for the Priestly Benediction; first for the New Moons; first for the prohibition of improvised altars; first for partaking of consecrated food; first for the descent of the fire, as it is written: “Fire emerged from before the Lord and consumed upon the altar…” (Leviticus 9:24).