“The rainbow will be seen in the cloud.”
-Noach 9:14
The Zohar (I:72b) states that the rainbow is one of the signs of the
future redemption.
Commentators note that the rainbow indicates the purification and refinement
that the world underwent by means of the Flood. Before the Flood the clouds were
very coarse, thus preventing a reflection of sunlight. Thereafter, however, the
clouds became more refined; they reflected sunlight, thus bringing about a
rainbow.
This, then, is the connection between the rainbow and the future redemption:
The entire world will attain the peak of refinement with the coming of Moshiach.