The ancient Israelites, fresh out of Egypt, knew that feeling all too well.

We find a fascinating glimpse into this in Shemot Rabbah, a collection of rabbinic interpretations on the Book of Exodus. Specifically, we’re looking at Shemot Rabbah 23, which grapples with the verse "Then Moses sang..." (Exodus 15:1). But what prompted this song? What was the spark that ignited their praise?

The verse "They believed in His words, they sang His praise" (Psalms 106:12) provides the key. Rabbi Abahu points out a crucial tension. It says in Exodus 4:31, "The people believed" while they were still in Egypt. So, were they already believers? Did they already have faith?

Not so fast, says Rabbi Abahu. He then quotes Psalms 106:7: "Our ancestors in Egypt did not comprehend Your wonders." It’s a stark reminder that belief isn't always a straight line. It's a journey, a process of fits and starts. They might have thought they believed in Egypt, but true faith, the kind that inspires song, was still to come.

So, what changed? What pushed them over the edge from tentative hope to full-throated praise? The sea. The moment they witnessed the full might of God, the way He enacts justice, as it says, "My hand grasps judgment" (Deuteronomy 32:41) and saw the Egyptians swallowed by the waves. That's when "They believed in God" (Exodus 14:31).

Az. That little Hebrew word, meaning "then." "Then Moses and the children of Israel sang." Shemot Rabbah tells us that az signifies faith. It's more than just a temporal marker; it's a spiritual marker. The text draws a parallel to Genesis 39:5, "It was from when [me’az] he appointed him in his house." This refers to Potiphar trusting Joseph completely and putting him in charge of his household. The word az, in this context, shows a complete trust, a total faith.

In other words, the song wasn't just a reaction to being saved. It was an expression of a newfound, unwavering faith. Az – the moment of true belief, the moment the Divine Spirit rested upon them, and the moment the song burst forth. "They believed in His words, they sang His praise."

What does this mean for us? Perhaps it's a reminder that faith isn't a static thing. It's not a box we check and then move on. It's something that needs to be constantly renewed, constantly tested, constantly deepened. And sometimes, it takes seeing the awesome power of the Divine, witnessing a miracle, to truly believe. It takes an az moment.