Talha bin Ubaydullah reported,

Umar saw Talha bin Ubaydullah looking troubled and said, "What is the matter with you, Abu so-and-so? Perhaps you are displeased that your cousin has been given command, Abu so-and-so?"Talha replied, "No, but I heard a hadith from the Messenger of Allah ﷺ that I never asked him about, though I had every opportunity to do so before he died. I heard him say, 'I know a word which no servant says at the moment of his death without his face becoming radiant because of it and Allah relieving him of his anguish.'"Umar said, "I know what it is."Talha asked, "And what is it?"Umar said, "Do you know of any word greater than the word he commanded his uncle to say at the moment of death? La ilaha illa Allah."Talha said, "You have spoken the truth. By Allah, that is it. That is it."

حدثنا أسباط حدثنا مطرف عن عامر

عن يحيى بن طلحة عن أبيه قال

رأى عمر طلحة بن عبيد الله ثقيلا فقال ما لك يا أبا فلان لعلك ساءتك إمرة ابن عمك يا أبا فلان قال لا إلا أني سمعت من رسول الله ﷺ حديثا ما منعني أن أسأله عنه إلا القدرة عليه حتى مات سمعته يقول إني لأعلم كلمة لا يقولها عبد عند موته إلا أشرق لها لونه ونفس الله عنه كربته قال فقال عمر رضي الله عنه إني لأعلم ما هي قال وما هي قال تعلم كلمة أعظم من كلمة أمر بها عمه عند الموت لا إله إلا الله قال طلحة صدقت هي والله هي