Many of the ungodly are disillusioned when God doesn’t answer their prayers. They need to know that He often doesn’t hear them because of their proud and sinful hearts. The psalmist warns that if we regard iniquity in our heart, the Lord will not hear (see Psa. 66:18). We must continually confess and forsake sin, and keep intimate communion with God. See also 1:15; Mic. 3:4; John 9:31.
Isaiah 59:1 Behold, the Lords hand is not shortened, Behold, the Lords hand is not shortened, That it cannot save; Nor His ear heavy, That it cannot hear.2 But your iniquities have separated you from your God; And your sins have hidden His face from you, So that He will not hear.
Ray Comfort's Daily Evidence 
I have heard this and try to continually repent. Doesn’t Christ cover for us once He is Lord of our lives?