2 Chronicles 7:14

And My people, who are called by My Name, humble themselves, and pray and seek (crave, require as a necessity) My face and turn from their wicked ways, then I will hear (them) from heaven, and forgive their sin and heal their land. 

God set a path before us to follow and clearly outlined the way. Man has free will and, due to lack of knowledge or rebellion, may follow another route that leads to sin. Sin then enters and separates us from God, and God cannot gulf the breach unless the sin is confessed and we repent. When we seek the face of God in repentance, we can breach the gulf and get answered prayer.