Shaybi reported,

Umar passed by Talha and noticed something concerning, so he mentioned it. Umar passed by Talha and saw him looking distressed.Umar asked, "Perhaps the leadership of your cousin has upset you?" meaning Abu Bakr .Talha replied, "No, but I heard the Messenger of Allah ﷺ say, 'I certainly know a word that no man says at the time of his death except that it becomes a light in his record, or his soul finds comfort in it at the moment of death.'"Umar said, "I will tell you what it is. It is the word he wanted his uncle to say, the testimony that there is no god but Allah."Talha said, "It was as though a veil had been lifted from me."Umar replied, "You have spoken the truth. Had he known a word better than it, he would have commanded him with that instead."

حدثنا يحيى عن إسماعيل حدثنا عامر وحدثنا محمد بن عبيد حدثنا إسماعيل بن أبي خالد عن رجل

عن الشعبي قال

مر عمر بطلحة فذكر معناه قال مر عمر بطلحة فرآه مهتما قال لعلك ساءك إمارة ابن عمك قال يعني أبا بكر رضي الله عنه فقال لا ولكني سمعت رسول الله ﷺ يقول إني لأعلم كلمة لا يقولها الرجل عند موته إلا كانت نورا في صحيفته أو وجد لها روحا عند الموت قال عمر أنا أخبرك بها هي الكلمة التي أراد بها عمه شهادة أن لا إله إلا الله قال فكأنما كشف عني غطاء قال صدقت لو علم كلمة هي أفضل منها لأمره بها