No benefit comes from a just man’s prayer if he who asks for it finds more pleasure in sin than in virtue. For Samuel mourned over Saul when he sinned, but he was not able to obtain God’s mercy, for his grief was not supported by the necessary change of life on the part of the sinner. Hence God put an end to the pointless grief of His servant, saying to him, ‘How long will you mourn for Saul, seeing I have rejected him from reigning over Israel?’ (1 Samuel 16:1)
~St Maximos the Confessor
Prayerful Life 