“But, if God is so merciful, why must we earnestly knock at his door in distress and pray, to have Him turn away from our petition? Scripture says: ‘Behold the hand of the Lord is not too short to save; nor his ear hard of hearing. But your iniquities have made a separation between you and God and your sins have turned his face from you, so that he does not hear…‘ (Isaiah 59:1-2)
God has wisely ordained these things of yours in this way for your own profit that you may continually knock at his door, and through the fear of sorrowful events his memory may constantly come to your mind. Then you will be near to God in constant petition and you will be sanctified by the continual memory of Him in your heart.
When you invoke Him and He answers you, you will know that your savior is God. And you will be aware of your God as the One who created you, your provider and keeper, because He has made two worlds for your sake: one as it were for your instruction as a school of brief duration, and the other as the house of your Father and your home forever and ever.”
(St. Isaac of Nineveh, On Ascetical Life, pp. 89-90)