"We all hear voices, it’s just a matter of choosing which ones we listen to…" That line is from the 2001 movie "A Beautiful Mind" by Russell Crowe who portrayed the mathematical genius John Nash. The movie pulls you in long before revealing that, because of Nash’s severe schizophrenia, many of the characters and events existed only in his mind. Then it unfolds how he learned to distinguish between what was real and what was made up in his mind. He learned which voices to listen to.
That's a powerful illustration of the dilemma for all humans; whose voice will we listen to? As Israel was getting ready to enter the Promised Land it was clear that Moses would soon die. God had used him as His spokesman to lead them out of Egypt and for forty years in the wilderness. How would they know what to do? God first told them not to listen to the soothsayers and charlatans that he was driving out of the land (Deuteronomy 18:9-14). Then He told them that He would send His chosen prophets to deliver His message (Deuteronomy 18:15-22).
This is where it gets difficult for all of us because so many people claim to speak for God. How do we sort through the voices and choose the right ones to listen to? God knew it was an issue so he asked and answered the question in the text. The simple answer is truth. If the prophet is from God the prophecy will come true and if it doesn't come true then the prophet is false (Deuteronomy 18:21-22). Since the ultimate fulfillment was Jesus, the embodiment of all truth, (John 14:6), and ultimate prophet (Acts 3:20-23), the real question is simple; Will we listen to him?