"And Ibn al-Qayyim confirmed a principle, saying that the human being, if his righteous deeds and benefit in the society are a lot, then he is forgiven for things that others might not be forgiven for, and mistakes of his may be overlooked that would not be overlooked for others, because the Messenger of Allah said: "If water reaches two qullahs (measuring unit), then it will not become impure by impurity." So, a large volume of water, if some small impurity falls into it, does not have its impurity affected, and it can still be used for ablution and bathing. Likewise, the human being, if his good deeds are many, then one turns a blind eye to some of his bad deeds that are drowning in his ocean of good deeds.
Because of this, when 'Umar was bursting with fury at Hatib bin Abi Balta'ah, the one who carried out the great crime of treason - the crime of spying on the Islamic state and sending secret messages to Quraysh - and said: "O Messenger of Allah! Let me strike his neck, as he has become a hypocrite," the Messenger of Allah took the opportunity to teach them this basic principle by way of real-life experience, saying: "And how do you know, 'Umar? He took part in the Battle of Badr, and it might be that Allah Looked to the participants of Badr and Said: 'Do what you wish, as I have Forgiven you.'""
['at-Tarbiyah al-Jihadiyyah wal-Bina''; 2/79]
(SHEIKH 'ABDULLAH YUSUF 'AZZAM (ASY-SYAHID, INSYAALLAH)