“The cloud covered the Tent of Meeting, and the glory of G-d filled the Tabernacle. Moshe could not enter the Tent of Meeting, for the cloud rested upon it, and the glory of G-d filled the Tabernacle. When the cloud was raised up from upon the Tabernacle, the Children of Israel would embark on all their journeys. If the cloud did not rise up, they would not embark until the day it rose up. For the cloud of G-d would be on the Tabernacle by day, and fire would be on it at night, before the eyes of all of the House of Israel throughout their journeys.” (Exodus 40:34-38)
After the completion of the Tabernacle, the cloud covered it during the day and the “glory of G-d”, which was the fire, covered it at night. There is no doubt that both the cloud and the fire were always present, the cloud and the fire within it. However, during the day only the cloud was seen, as it shielded the fire, while at night, in the darkness, only the fire within could be seen. Their journeys were dependent on whether or not the cloud/fire was resting on the Tabernacle or was raised above it.
A teaching of Rabbi Akiva the son of Rabbi Yossi is quoted in the Midrash Tanchuma (Pekudei 12): “Why does it say (Psalms 26:8): ‘G-d, I love the shelter of Your House and the place of the residence of Your glory?’ The answer is that G-d’s House is compared to the creation of the universe. Regarding the Tabernacle the Torah states, ‘And you shall make the curtains’ (Exodus 26:7). Regarding the creation of the universe it is written, ‘Who spreads the heavens like a thin curtain’ (Isaiah 40:22), and ‘...stretching out the heavens like a curtain’ (Psalms 104:2). In the Tabernacle it is written, ‘...and the partition shall separate for you between the Holy and the Holy of Holies’ (Exodus 26:33), and in the creation narrative it states, ‘Let there be a firmament in the midst of the waters, and let it separate between water and water’ (Genesis 1:6). In the Tabernacle it states, ‘You should make a copper laver...and put water there’ (Exodus 30:18). In the creation narrative: ‘Let the waters beneath the heavens be gathered into one area’ (Genesis 1:9). In the Tabernacle the Menorah stood to give off light; in creation G-d created the luminaries to give off light. The Tabernacle had the Cherubim with their wings spread upwards, and G-d created fowl that fly across the expanse of the heavens. The Torah tells us that all the work of the Tabernacle was completed; G-d says that the heavens and the earth were finished. When they had finished the Tabernacle Moshe blessed them; so too, G-d blessed the seventh day. Moshe sanctified the Tabernacle and all of its utensils; similarly G-d blessed the seventh day and sanctified it. Finally, in the midst of the commandments regarding the building of the Tabernacle Moshe tells the people that on six days work may be done, but the seventh is Shabbat, a day holy to G-d; this is parallel to Gd’s statement in the creation narrative,“G-d blessed the seventh day and sanctified it because on it He abstained from all His work which G-d created to make. (Genesis 2:3).”
Thus, the Tabernacle and its utensils hint at the nature of all that was brought into existence at the time of creation. And just as the activities of the first six days of creation were a preparation for the fixed natural order that would continue from the seventh day and onward, the activities that went into the building of the Tabernacle were to prepare the dwelling place for the Divine Presence. Once the Tabernacle was completed, G-d’s presence and His Divine Providence would be fully manifested. This is another reason why Moshe mentions the mitzvah of Shabbat along with the completion of the Tabernacle.
Finally, to complete the parallel between the Tabernacle and the creation, the end of this Torah portion, which concludes the Book of Exodus, tells us that the Children of Israel travelled only when the cloud of glory was lifted. Just as nothing in the universe moves without G-d’s direction, so too the Children of Israel journeyed only when He directed them to do so. Thus, just as G-d created the universe, formed it and set it in motion, so too with His commands He brought about the construction of the Tabernacle, and directed its movement through the journeys of the nation in the Wilderness.