That God does not easily pardon idolaters
Moses in Exodus prays for the people, and does not obtain his prayer, saying: “I pray, O Lord, this people has sinned a great sin. They have made them gods of gold. And now, if You forgive them their sin, forgive it; but if not, blot me out of the book which You have written. And the Lord said unto Moses, If any one has sinned against me, him will I blot out of my book.” Moreover, when Jeremiah besought for the people, the Lord speaks to him, saying: “And pray not for this people, and entreat not for them in prayer and supplication; because I will not hear in the time wherein they shall call upon me in the time of their affliction.” Ezekiel also denounces this same anger of God upon those who sin against God, and says: “And the word of the Lord came unto me, saying, Son of man, whatsoever land sins against me, by committing an offense, I will stretch forth mine hand upon it, and will crush the support of the bread thereof; and I wills send into it famine, and I will take away from it man and beast.
And though these three men were in the midst of it, Noah, Daniel, and Job, they shall not deliver sons nor daughters; they themselves only shall be delivered.” Likewise in the first book of Kings: “If a man sin by offending against another, they shall beseech the Lord for him; but if a man sin against God, who shall entreat for him?”
Source: The Treatises of Cyprian (New Advent)