St. Ephraim the Syrian:
4. Moses sweetened in Marah the waters that were bitter, — because the People complained and murmured: — Thus he gave a sign of baptism, — wherein the Lord of life makes sweet them that were bitter.
5. The cloud overshadowed and kept off the burning heat from the camp; — it showed a symbol of the Holy Spirit, which overshadows you in baptism — tempering the flaming fire that it harm not your bodies.
6. Through the sea the People then passed, and showed a symbol — of the baptism wherein ye were washed. The People passed through that and believed not: — the Gentiles were baptized in this and believed and received the Holy Ghost.
7. The Word sent the Voice to proclaim before His Coming, — to prepare for Him the way by which He came, — and to betroth the Bride till He should come, — that she might be ready when He should come and take her from the water.
(Fifteen Hymns on the Feast of Epiphany, Hymn 1, NPNF2.11)