It was narrated from Yahya bin Talhah that his father said

`Umar(رضي الله عنه) saw Talhah bin `Ubaidullah looking upset and said: “What is the matter with you, O Father of so and so? Perhaps your cousin being appointed as caliph has upset you, O Father of so and so?” He said: “No, but I heard a Hadeeth from the Messenger of Allah (ﷺ) and nothing prevented me from asking him about it except the fear of not being able to comply with it sand I did not ask him about it until he died. I heard him say: `I know a word which no one says at the time of death but his colour will brighten and Allah will relieve him of his distress.` Umar (رضي الله عنه) said: “I know what it is.” Talhah said: “What is it?” ’Umar(رضي الله عنه) 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.”