What does Exodus 3:13 mean?
When God commanded Moses to go back to Egypt and lead Israel out of slavery (Exodus 3:9–10), Moses' first response was an expression of doubt (Exodus 3:11). God replied with reassurances, both of His own presence, and with prophecy of Moses' eventual success (Exodus 3:12).Here, Moses provides a second objection. His first excuse was related to his own identity, suggesting he was no one special or powerful enough to succeed. The excuse given here relates to God's identity. Moses' request is not entirely inappropriate. He expects people to ask a very natural question: who sent you to lead us? Specifically, Moses wants to know how to answer the question of "which God" he is representing. This interesting question leads to a unique revelation of the Lord's name in the next verse (Exodus 3:14); this statement will become an integral part of God's identity as revealed in the rest of Scripture.
The phrase, "The God of your fathers," relates back to a similar comment made by God (Exodus 3:6), implying that the One speaking is the God of Moses' ancestors. Moses uses an important shift in perspective, however. In Moses' words, this being is "the God of your fathers," as spoken by Moses to the Jewish people. In other words, this emphasizes God's relationship to the Hebrew people, rather than to Moses. Moses has a conflicted identity with the Hebrews. He is a Jew, but was not raised as a Jew (Exodus 2:10). He is one of the enslaved Israelites, ethnically, yet lives in exile (Exodus 2:14–15) and away from that slavery. Moses is understandably nervous to approach the Jewish people and demand they obey his instructions. Even when he lived in Egypt, the Hebrew people saw no reason to think of him as an authority figure (Exodus 2:14).
So, Moses seeks advice from God regarding how to respond, still hoping God will choose someone else instead.