God's voice is heard only by those shut up with him alone in secret prayer who have learned how to wait on the Lord. God is very careful to whom he speaks. It is only to those who value his voice so much they shut out the whole world to get alone with him. If we know the voice of God we will not be led astray by another voice. From Hebrews 12:23-27 he goes to a number of scriptures on how God has spoken and conversed with his prophets and saints throughout the whole Bible. We can talk and walk with God today, if we are willing to make time for him and listen to him.