Genesis 9:14-17 meaning

God's grace is seen in the sign of the rainbow, the seal of His covenant promise never to destroy all life by flood again. God used the rain and water to bring about His judgment on the earth. Now, the rainbow (a meteorological phenomenon) which is associated with rain would be an image or symbol of God's covenant.

The text infers that the rainbow is something new. That underscores the reality that "the world at that time was destroyed" (2 Peter 3:6). The new earth after the flood is substantially different from the earth prior to the flood. It seems likely that the atmosphere is now substantially different. It could be that there was a canopy of vapor surrounding the earth that is now collapsed, accounting for the 40 days of rain followed by the appearance of a rainbow.

In verse 15, God states, I will remember my covenant. Not that God forgets, but because of being described in the language of men, who are forgetful and need help with their memory, it is described this way. The Noahic covenant helps us understand the character of God as seen through Him as a covenant-maker. Every time we see a rainbow, we should remember the justice and the faithfulness of God. God will honor every one of His promises. God does not forget, and He does not change.