Sahih Bukhari Book: 2, Hadith: 51

حَدَّثَنَا إِبْرَاهِيمُ بْنُ حَمْزَةَ، قَالَ حَدَّثَنَا إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنْ صَالِحٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ، أَنَّ عَبْدَ اللَّهِ بْنَ عَبَّاسٍ، أَخْبَرَهُ قَالَ أَخْبَرَنِي أَبُو سُفْيَانَ، أَنَّ هِرَقْلَ، قَالَ لَهُ سَأَلْتُكَ هَلْ يَزِيدُونَ أَمْ يَنْقُصُونَ، فَزَعَمْتَ أَنَّهُمْ يَزِيدُونَ، وَكَذَلِكَ الإِيمَانُ حَتَّى يَتِمَّ‏.‏ وَسَأَلْتُكَ هَلْ يَرْتَدُّ أَحَدٌ سَخْطَةً لِدِينِهِ بَعْدَ أَنْ يَدْخُلَ فِيهِ، فَزَعَمْتَ أَنْ لاَ، وَكَذَلِكَ الإِيمَانُ حِينَ تُخَالِطُ بَشَاشَتُهُ الْقُلُوبَ، لاَ يَسْخَطُهُ أَحَدٌ‏.‏ Narrated ‘Abdullah bin ‘Abbas:I was informed by Abu Sufyan that Heraclius said to him, “I asked youwhether they (followers of Muhammad) were increasing or decreasing.You replied that they were increasing. And in fact, this is the way of true Faith till it is complete in all respects. I further asked youwhether there was anybody, who, after embracing his (the Prophets)religion (Islam) became displeased an...