Musnad Ahmad 1386
It was narrated from Yahya bin Talhah bin `Ubaidullah, from his father, that ‘Umar (رضي الله عنه) saw him looking sad and said:
“What is the matter with you, O Abu Muhammad? Perhaps you are upset about your cousin being appointed as caliph?” [referring to Abu Bakr(رضي الله عنه)]. He said: “No.” And he spoke highly of Abu Bakr (رضي الله عنه), [then he said:] “But I heard the Prophet (ﷺ) say: `[There is] a word which no one says when he is dying but Allah will relieve him of distress and his colour will brighten.” Nothing prevented me from asking him about it except the fear of not being able to comply with it and I did not ask him about it until he died.” ‘Umar said to him: “I know what it is.” Talhah said to him: “What is it?` ‘Umar said: “Do you know any word that is greater than the word he enjoined his uncle to say when he was dying, ‘La ilaha illallah’?” Talhah said: “You are right. By Allah, that is what it is.”
حَدَّثَنَا إِبْرَاهِيمُ بْنُ مَهْدِيٍّ، حَدَّثَنَا صَالِحُ بْنُ عُمَرَ، عَنْ مُطَرِّفٍ، عَنْ الشَّعْبِيِّ، عَنْ يَحْيَى بْنِ طَلْحَةَ بْنِ عُبَيْدِ اللَّهِ، عَنْ أَبِيهِ، أَنَّ عُمَرَ، رَضِيَ اللَّهُ عَنْهُ رَآهُ كَئِيبًا فَقَالَ مَا لَكَ يَا أَبَا مُحَمَّدٍ كَئِيبًا لَعَلَّهُ سَاءَتْكَ إِمْرَةُ ابْنِ عَمِّكَ يَعْنِي أَبَا بَكْرٍ قَالَ لَا وَأَثْنَى عَلَى أَبِي بَكْرٍ رَضِيَ اللَّهُ عَنْهُ وَلَكِنِّي سَمِعْتُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ كَلِمَةٌ لَا يَقُولُهَا عَبْدٌ عِنْدَ مَوْتِهِ إِلَّا فَرَّجَ اللَّهُ عَنْهُ كُرْبَتَهُ وَأَشْرَقَ لَوْنُهُ فَمَا مَنَعَنِي أَنْ أَسْأَلَهُ عَنْهَا إِلَّا الْقُدْرَةُ عَلَيْهَا حَتَّى مَاتَ فَقَالَ لَهُ عُمَرُ رَضِيَ اللَّهُ عَنْهُ إِنِّي لَأَعْلَمُهَا فَقَالَ لَهُ طَلْحَةُ وَمَا هِيَ فَقَالَ لَهُ عُمَرُ رَضِيَ اللَّهُ عَنْهُ هَلْ تَعْلَمُ كَلِمَةً هِيَ أَعْظَمَ مِنْ كَلِمَةٍ أَمَرَ بِهَا عَمَّهُ لَا إِلَهَ إِلَّا اللَّهُ فَقَالَ طَلْحَةُ هِيَ وَاللَّهِ هِيَ‏.‏