'Reu,' as in Genesis 11:18, signifies a more external form of worship than that signified by 'Peleg,' his father.

(References: Arcana Coelestia 1347)

In Exodus 15:8, this signifies falsities gathered together. Waters normally signify truths, but in this case, where they were blocking the escape of the Children of Israel from slavery and signify the opposite: falsities.

(References: Arcana Coelestia 8286)