Albert Barnes Commentary Ezekiel 1:28

"As the appearance of the bow that is in the cloud in the day of rain, so was the appearance of the brightness round about. This was the appearance of the likeness of the glory of Jehovah. And when I saw it, I fell upon my face, and I heard a voice of one that spake." — Ezekiel 1:28 (ASV)

The rainbow is not simply a token of glory and splendor. The “cloud” and the “day of rain” point to its original message of forgiveness and mercy, and this is especially suited to Ezekiel’s commission, which was first to denounce judgment, and then promise restoration.