In the tabernacle, blue appears regularly as the sacred colour representing the divine presence of the shekinah glory. See Ex 26:4, 31, 36:23, 35, 39:1, etc.
In the Epiphanes of Psalms and Ezekiel, we see the domination of the colour blue again associated with the personal presence of God.
- Eze 1:26 - Above the expanse over their heads was the likeness of a throne with the appearance of sapphire, and on the throne high above was a figure like that of a man.
- Eze 10:1 - I looked, and I saw the likeness of a throne of lapis lazuli above the vault that was over the heads of the cherubim.
In many places, God is described as "enthroned between the cherubim" which the desert tabernacle was to represent, particularly the Ark of the Covenant, 1 Chron 13:6, 2 Kings 19:15, 1 Sam 4:4, Ps 80:1, 99:1, 2 Sam 6:2, Isa 37:16, etc.