The dwelling places and assemblies of Mount Zion mentioned in Isaiah 4:5 mean, respectively, the good of the celestial church and the truths of that good.

(References: Apocalypse Explained 594)

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)