Hadith 509910
Chapter 21: Jihad - كتاب الجهاد
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، كَانَ يَقُولُ اللَّهُمَّ لاَ تَجْعَلْ قَتْلِي بِيَدِ رَجُلٍ صَلَّى لَكَ سَجْدَةً وَاحِدَةً يُحَاجُّنِي بِهَا عِنْدَكَ يَوْمَ الْقِيَامَةِ .
Yahya related to me from Malik from Zayd ibn Aslam that Umar ibn al-Khattab used to say, "O Allah! Do not let me be slain by the hand of a man who has prayed a single prostration to You with which he will dispute with me before You on the Day of Rising!"
Reference Muwatta Malik 509910
USC-MSA web (English) reference : Book 21, Hadith 30