Muwatta Malik, Book 43, Hadith 1590 (In-Book) ⓘ

Malik said that he had heard that Said ibn al-Musayyab and Sulayman ibn Yasar were asked, "Does one deal more harshly in taking the blood-money in the sacred month?" They said, "No. But it is increased in it because of violating the month." It was said to Said, "Does one increase for the wound as one increases for the life?" He said, "Yes." Malik added, "I think that they meant the same as what Umar ibn al-Khattab did with respect to the blood-money of the Mudliji when he struck his son." (i.e. giving 120 camels instead of 100).

وَحَدَّثَنِي مَالِكٌ، أَنَّهُ بَلَغَهُ أَنَّ سَعِيدَ بْنَ الْمُسَيَّبِ، وَسُلَيْمَانَ بْنَ يَسَارٍ، سُئِلاَ أَتُغَلَّظُ الدِّيَةُ فِي الشَّهْرِ الْحَرَامِ فَقَالاَ لاَ وَلَكِنْ يُزَادُ فِيهَا لِلْحُرْمَةِ ‏.‏ فَقِيلَ لِسَعِيدٍ هَلْ يُزَادُ فِي الْجِرَاحِ كَمَا يُزَادُ فِي النَّفْسِ فَقَالَ نَعَمْ ‏.‏ قَالَ مَالِكٌ أُرَاهُمَا أَرَادَا مِثْلَ الَّذِي صَنَعَ عُمَرُ بْنُ الْخَطَّابِ فِي عَقْلِ الْمُدْلِجِيِّ حِينَ أَصَابَ ابْنَهُ ‏.‏