When God described Himself to Moses, He said, "I Am Who I Am". (Deuteronomy 4:14)
I Am Who I Am can mean different things to different people because we can see from the Bible that God reveals himself to people in the way they can understand Him.
For example when He was talking to the Israelites in the wilderness after delivering them from Egypt, Moses told the Israelites not to forget the Lord's covenant and make carved images because The Lord your God is a consuming fire. (Deuteronomy 4:24)
God even came to the foot of the mountain and The mountain burned with fire to the midst of heaven. (Deuteronomy 4:24)
Moses also told them, "The Lord God talked with you face to face on the mountain from the middle of the fire." (Deuteronomy 5:4-5)
God revealed Himself to the Israelites as a consuming fire when He gave them the 10 commandments. Click the link to read The 10 Commandments.
By speaking to them from the middle of the fire, the Israelites acknowledged that God has shown us His glory and His greatness. (Deuteronomy 5:24)
Speaking to the Israelites from the middle of the fire when He was giving them the 10 Commandments and in so doing revealing his greatness and His glory, suggests that God expected them to take His Commandments seriously.
This was in contrast with other times when God appeared to the Israelites at the entrance of the Tabernacle of the Meeting.
This consuming fire also made the Israelties afraid and they asked Moses to be their mediator and tell them what God had said. Being afraid of God was also more likely to increase their chances of obeying the 10 Commandments.