When the Crusaders killed more than 60,000 Muslim men, women and children.
Ibn Kathir said:
وفيها أخذت الفرنج بَيْتَ الْمَقْدِسِ لَمَّا كَانَ ضُحَى يَوْمَ الْجُمُعَةِ لِسَبْعٍ بَقِينَ مِنْ شَعْبَانَ سَنَةَ ثِنْتَيْنِ وَتِسْعِينَ وأربعمائة، أخذت الْفِرِنْجُ لَعَنَهُمُ اللَّهُ بَيْتَ الْمَقْدِسِ شَرَّفَهُ اللَّهُ، وكانوا في نحو ألف ألف مقاتل، وقتلوا في وسطه أزيد من ستين أَلْفَ قَتِيلٍ مِنَ الْمُسْلِمِينَ، وَجَاسُوا خِلَالَ الدِّيَارِ، وتبروا ما علوا تتبيرا.
Friday morning 23rd Shaban 493 h the Christians took control of Bayt all Maqdas, May Allah curse them. They were thousand and thousands and killed more than 60,000 Muslims, went in to the houses of Muslims and spread the destruction. [Al Bidaya wal Nihaya 12/156]
After 90 years of their rule, in the battle of Hattin Sultan ul Muwahhideen, Salah al DIin Ayyubi ordered the Muslim Army to ask Allah’s help.
Ibn Kathir said:
ثم أمر السلطان بالتكبير والحملة الصادقة فحملوا وكان النَّصْرُ مِنَ اللَّهِ عَزَّ وَجَلَّ، فَمَنَحَهُمُ اللَّهُ أكتافهم فَقُتِلَ مِنْهُمْ ثَلَاثُونَ أَلْفًا فِي ذَلِكَ الْيَوْمِ، وَأُسِرَ ثَلَاثُونَ أَلْفًا مِنْ شُجْعَانِهِمْ وَفُرْسَانِهِمْ،
The Sultan ordered to say Takbeer and attack. They attacked and Allah gave them victory.. and killed their 30,000 soldiers. and 30,000 of their soldiers were captured. [Al Bidaya wal Nihaya 12/321]
Finally, at the gates of Jerusalem.
When the Sultan defeated the Christians after a great fight, their leader came and asked for Amaan, The Sultan wanted to kill all the Christians men as they brutally killed Muslim, Men, women and children in Jerusalem. Their leader said:
إن لَمْ تُعْطِنَا الْأَمَانَ رَجَعْنَا فَقَتَلْنَا كُلَّ أَسِيرٍ بأيدينا- وكانوا قريبا من أربعة آلاف- وقتلنا ذرارينا وأولادنا ونساءنا، وخربنا الدور والأماكن الحسنة، وأحرقنا المتاع وأتلفنا ما بأيدينا من الأموال، وهدمنا قبة الصخرة وحرقنا ما نقدر عليه، وَلَا نُبْقِي مُمْكِنًا فِي إِتْلَافِ مَا نَقْدِرُ عليه، وبعد ذلك نخرج فنقاتل قتال الموت، ولا خير في حياتنا بعد ذلك، فَلَا يُقْتَلُ وَاحِدٌ مِنَّا حَتَّى يَقْتُلَ أَعْدَادًا مِنْكُمْ، فَمَاذَا تَرْتَجِي بَعْدَ هَذَا مِنَ الْخَيْرِ؟
If you are not going to give us amaan, we will go back and kill the Muslim Hostages who are approx 4000, we will also kill our sons and daughters, and destroy the houses and other places, We will fire the equipment, and destroy the dome of rock.. then we will come out again and fight for death… [Al Bidaya wal Nihaya 12/323]
Then the Sultan gave all of them amaan with some sharait. And Allah honored the Mujahideen.
When Salah ud din wanted to destroy the Church.
Ibn Kathir said, He wanted to destroy a very old and sacred church according to the Christians but He was told that:
وقد فتح هذه البلد قبلك أَمِيرُ الْمُؤْمِنِينَ عُمَرُ بْنُ الْخَطَّابِ وَتَرَكَ هَذِهِ الكنيسة بأيديهم، ولك فِي ذَلِكَ أُسْوَةٌ. فَأَعْرَضَ عَنْهَا وَتَرَكَهَا عَلَى حالتها تأسيا بعمر رضى الله عنه، ولم يترك من النصارى فيها سِوَى أَرْبَعَةٍ يَخْدُمُونَهَا، وَحَالَ بَيْنَ النَّصَارَى وَبَيْنَهَا، وَهَدَمَ الْمَقَابِرَ الَّتِي كَانَتْ لَهُمْ عِنْدَ بَابِ الرحمة، وعفا آثَارَهَا، وَهَدَمَ مَا كَانَ هُنَاكَ مِنَ الْقِبَابِ.
Previously Umar bin al Khattab took control of this city, but He left this church on their (Christians) hands, He has set an example for you. So He left the church and followed Umar May Allah be pleased with him… And he destructed the shrines and the left overs near the baab al Rahmah and also destroyed the domes over them. [al Bidaya wal Nihaya 12/327]