Challenging the Notion of Learning to Hear God's Voice

Questions about why, if we don’t need to learn to hear God’s voice, there’s a command to earnestly desire the gift of prophecy, why we would need to learn how to use other spiritual gifts but not this one, and why there are men who don’t perceive God’s voice in Job 33:14.  

• You say we don’t need to learn to hear the voice of God, but we’re commanded to “earnestly desire the spiritual gifts, especially that you may prophesy” (1 Cor. 14:1) and to “earnestly desire to prophesy” (1 Cor. 14:39), and passages like these seem to be prescriptive texts (1 Cor. 14:37; 1 Thess. 5:20; Rom. 12:6).
• Just as someone who has been given the gift of teaching by the Holy Spirit has to learn how to exegete a passage, so those with the gift of prophecy have to learn how to hear God’s voice.
• If it’s impossible to miss God’s voice, why are there men who don’t perceive his voice in Job 33:14?