Do you often hear the voice of God? Did you even know that He still speaks today? In Psalms 62:11 the writer says, "Once God has spoken; Yet these two things I have heard..."
The value of a discerning ear should not be underestimated. God is very judicious with His words and often buries priceless truths in one very simple yet profound statement.
When you read your Bible, what do you hear God speaking? When you listen to a preacher, what do you hear God saying? When you talk to Him in prayer, what do you hear Him telling you? The discerning ear will always try to hear the less obvious and unearth new applications to vintage revelation.
God may speak once but if we are careful and discerning, we can get more out of what He said than just what He said. Live right, live well...