The rainbow is God's covenant sign because it symbolizes His promise never again to destroy the whole earth by a flood. After the Flood, God made a covenant with Noah, his descendants, and every living creature, saying, "I do set my bow in the cloud, and it shall be for a token of a covenant between me and the earth" (Genesis 9:13, KJV). Whenever a rainbow appears in the clouds, it serves as a reminder of God's faithfulness and His enduring promise that "neither shall all flesh be cut off any more by the waters of a flood" (Genesis 9:11, KJV). Throughout the Bible, the rainbow is also associated with God's glory and majesty (Ezekiel 1:28; Revelation 4:3), making it a beautiful symbol of His mercy, faithfulness, and unchanging covenant with creation.