I entered the mosque. The Messenger of Allah (Allah bless him and grant him peace) was seated there with the people around him. Ṭalḥah ibn ʿUbayd Allah (may Allah be pleased with him) jumped up and hurried toward me; he grasped my hand and congratulated me. By Allah, none of the Emigrants rose to greet me except him, and I shall never forget what Ṭalḥah did.
Kaʿb said: When I saluted the Messenger of Allah (Allah bless him and grant him peace), his face was radiant with joy and he said, “Rejoice in the best day that has ever come to you since the day your mother bore you!”
I asked, “Is this from you, O Messenger of Allah, or from Allah?”
He replied, “No, rather it is from Allah.” Whenever the Messenger of Allah (Allah bless him and grant him peace) was delighted, his face would glow until it seemed as though it were a piece of the moon, and we recognized that in him.
After I had sat before him I said, “O Messenger of Allah, as part of my repentance I wish to give away all of my wealth in charity for Allah’s sake and for His Messenger.”
He said, “Keep some of your wealth; that is better for you.”
So I answered, “I shall keep my share in Khaybar.” Then I added, “O Messenger of Allah, Allah saved me only through truthfulness, and my repentance is that for the rest of my life I will speak nothing but the truth.”
By Allah, from the day I said that to the Messenger of Allah (Allah bless him and grant him peace) until today, I do not know that anyone among the Muslims has been tried more than I in maintaining truthful speech, and I hope that Allah will protect me for the rest of my life.
Then Allah revealed: “Allah has turned in mercy to the Prophet, the Emigrants, and the Helpers who followed him in the hour of hardship…” until His words, “Surely He is Kind and Merciful to them,” and He revealed regarding “the three who were left behind until, when the earth, vast as it is, became narrow for them…” until the words, “and be with the truthful” (Surah al-Tawbah 9:117–119).
Kaʿb said: By Allah, after Allah guided me to Islam, no blessing has ever meant more to me than my having been truthful before the Messenger of Allah.