Abu Hurayra reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "The person who is strong is not strong because he can knock people down. The person who is strong is the one who controls himself when he is angry."  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ لَيْسَ الشَّدِيدُ بِالصُّرَعَةِ إِنَّمَا الشَّدِيدُ الَّذِي يَمْلِكُ نَفْسَهُ عِنْدَ الْغَضَبِ  

Ibn 'Umar said, "There is nothing that is swallowed greater with Allah in reward than a slave of Allah who swallows and contains his rancour out of desire for the pleasure of Allah."  

مَا مِنْ جَرْعَةٍ أَعْظَمَ عِنْدَ اللهِ أَجْرًا مِنْ جَرْعَةِ غَيْظٍ كَظَمَهَا عَبْدٌ ابْتِغَاءَ وَجْهِ اللهِ  

"I seek refuge with Allah from the Accursed Shaytan."' The man went to that man and said, 'Do you know what he said? He said, "I seek refuge with Allah from the Accursed Shaytan."' The man retorted. 'Do you think me mad?'"  

اسْتَبَّ رَجُلاَنِ عِنْدَ النَّبِيِّ ﷺ فَجَعَلَ أَحَدُهُمَا يَغْضَبُ وَيَحْمَرُّ وَجْهُهُ فَنَظَرَ إِلَيْهِ النَّبِيُّ ﷺ فَقَالَ إِنِّي لَأَعْلَمُ كَلِمَةً لَوْ قَالَهَا لَذَهَبَ هَذَا عَنْهُ أَعُوذُ بِاللَّهِ مِنَ الشَّيْطَانِ الرَّجِيمِ فَقَامَ رَجُلٌ إِلَى ذَاكَ الرَّجُلِ فَقَالَ تَدْرِي مَا قَالَ؟ قَالَ قُلْ أَعُوذُ بِاللَّهِ مِنَ الشَّيْطَانِ الرَّجِيمِ فَقَالَ الرَّجُلُ أَمَجْنُونًا تَرَانِي؟  

A variant of the previous hadith.  

كُنْتُ جَالِسًا مَعَ النَّبِيِّ ﷺ وَرَجُلاَنِ يَسْتَبَّانِ فَأَحَدُهُمَا احْمَرَّ وَجْهُهُ وَانْتَفَخَتْ أَوْدَاجُهُ فَقَالَ النَّبِيُّ ﷺ إِنِّي لَأَعْلَمُ كَلِمَةً لَوْ قَالَهَا لَذَهَبَ عَنْهُ مَا يَجِدُ فَقَالُوا لَهُ إِنَّ النَّبِيَّ ﷺ قَالَ تَعَوَّذْ بِاللَّهِ مِنَ الشَّيْطَانِ الرَّجِيمِ قَالَ وَهَلْ بِي مِنْ جُنُونٍ؟  

Ibn 'Abbas said, "The Messenger of Allah, may Allah bless him and grant him peace, said, ' Teach and make it easy. Teach and make it easy.' three times. He went on, 'When you are angry, be silent' twice."  

قَالَ رَسُولُ اللهِ ﷺ عَلِّمُوا وَيَسِّرُوا عَلِّمُوا وَيَسِّرُوا ثَلاَثَ مَرَّاتٍ وَإِذَا غَضِبْتَ فَاسْكُتْ مَرَّتَيْنِ  

'Ali was heard to say to Ibn al-Kawwa', "Do you know what the first one said? 'Loving the one you love is an easy matter. It may be that one day he will be the one you hate. Hating the one who hate is an easy matter, It may be that one day he will be the one you hate.'"  

لِابْنِ الْكَوَّاءِ هَلْ تَدْرِي مَا قَالَ الأَوَّلُ؟ أَحْبِبْ حَبِيبَكَ هَوْنًا مَا عَسَى أَنْ يَكُونَ بَغِيضَكَ يَوْمًا مَا وَأَبْغِضْ بَغِيضَكَ هَوْنًا مَا عَسَى أَنْ يَكُونَ حَبِيبَكَ يَوْمًا مَا  

Aslam said, " 'Umar ibn al-Khattab said, 'Do not let your love be a total infatuation. Do not let your anger be destruction.' I asked, 'How is that?' He replied, 'When you love, you are infatuated like a child. When you hate, you desire destruction for your companion.'"  

لاَ يَكُنْ حُبُّكَ كَلَفًا وَلاَ بُغْضُكَ تَلَفًا فَقُلْتُ كَيْفَ ذَاكَ؟ قَالَ إِذَا أَحْبَبْتَ كَلِفْتَ كَلَفَ الصَّبِيِّ وَإِذَا أَبْغَضْتَ أَحْبَبْتَ لِصَاحِبِكَ التَّلَف