The answer is: In a burning bush

Exo 3:2

When Moses first encountered the angel of the Lord in the form of a burning bush, it marked the beginning of a pivotal chapter in the narrative of Israel's liberation from Egypt. Imagine Moses, tending sheep in the arid wilderness of Midian—how mundane! Suddenly, amidst the dry, ordinary landscape, he sees what appears to be a complete novelty: a bush aflame but never consumed. This miraculous sight didn’t just catch his attention; it encapsulated profound symbolism.

The fire represents God's presence, often referred to as "theophany," a fancy term for when God makes Himself known. In the context of ancient Israelite culture, fire also indicates purity and carries connotations of the divine—often connected with holiness. This encounter also delivered an event that reminds us of Jacob’s ladder and God speaking from a cloud at Mount Sinai, showing us how God often communicated through extraordinary signs.

As Moses ventured closer, hesitantly stepping into that sacred space, he was met by a mandate that changed history: “I am sending you to lead My people.” Just like that, Moses was thrown into a role no one would’ve expected, showing how anyone can take on monumental tasks for the greater good, perhaps even surprising themselves along the way.

So, the next time you hear of a Biblical moment of revelation, remember this incident for its deep symbolism, serving as a reminder that profound truths often come from the most unexpected encounters.