Why are God and the voice/Jehovah used synonymously in the burning bush passage?
The terms are interchangeable in this passage because the speaker is Christ, who is God. Scripture presents Him as the angel of the Lord, the Redeemer, God the Son, and Jehovah, yet He is also called God. This is why the voice from the bush can be identified as both Jehovah and God without contradiction.
Les explains that all the way through these verses, God and the voice, which is Jehovah, are used synonymously. The reason is that Christ is God. Les emphasizes this because one of the first signs of the cults is that they do not recognize Christ as God, but the Scripture does. In this burning bush account, even though the speaker is Christ, the angel of the Lord, the Redeemer, God the Son, and Jehovah, He is also called God. So God called to Moses from the midst of the bush, and Moses was told to put off his shoes because the place was holy ground. The passage also identifies Him as the God of Abraham, Isaac, and Jacob.