Ligon Duncan

“For this reason, the rainbow may represent the bow (weapon) of God and that it has been placed at rest in the clouds as a symbol of God’s rest from judgment (see Deut. 32:23, 42; Pss. 7:12[13]; 18:14[15]; Hab. 3:9). It is also worth noting that the rainbow is a feature associated with the throne of God and the divine presence: “Like the appearance of the [rain]bow in the clouds on the day of rain, so is the appearance of the brightness around him” (Ezek. 1:28). This theme is picked up in the book of Revelation, where the clouds and the rainbow attend the divine presence: “And I saw another strong angel coming down from heaven clothed with a cloud and the rainbow was around his head” (Rev. 10:1; see 4:3). Perhaps the rainbow represents God’s royal presence as the one who rules this world and sustains the covenant of common grace.55 We know that Yahweh sits enthroned over the flood,”
― Ligon Duncan, Covenant Theology: Biblical, Theological, and Historical Perspectives