Above the firmament over their heads something like a throne could be seen, looking like sapphire. Upon it was seated, up above, one who had the appearance of a man. Upward from what resembled his waist I saw what gleamed like electrum; downward from what resembled his waist I saw what looked like fire; he was surrounded with splendor. Like the bow which appears in the clouds on a rainy day was the splendor that surrounded him. Such was the vision of the likeness of the glory of the LORD. (Ez 1:2-5, 24-28c)
https://bible.usccb.org/bible/readings/081224.cfm
Sometimes a rainbow is just a rainbow . . . but in the vision of Ezekiel a rainbow is the glory of the Lord. For the next two weeks our Summer of the Prophets comes to a conclusion with the great prophet Ezekiel. In the tragedy of the Exile, Ezekiel sees the promise of restoration when God will write the covenant on our hearts.