Ibn Mansur said: "I said to Ahmad: 'The Prophet (saws) gave the Nafl when he divided the fourth, after the Khumus, and when he was returning (he gave) the third from the Khumus.' So he said: 'The Khumus is taken, and then the Nafl is given from what remains, nothing beyond this.''"

[Abu 'Eisa said:] This Hadith is (understood) as Ibn Musayyab said: "The Nafl is from te Khumus." Ishaq said as he said.

Who, from among Ka`b's sons, was the guide of Ka`b when he became blind: I heard Ka`b bin Malik narrating the story of (the Ghazwa of) Tabuk in which he failed to take part. Ka`b said, "I did not remain behind Allah's Apostle in any Ghazwa that he fought except the Ghazwa of Tabuk, and I failed to take part in the Ghazwa of Badr, but Allah did not admonish anyone who had not participated in it, for in fact, Allah's Apostle had gone out in search of the caravan of Quraish till Allah made them (i.e. the Muslims) and their enemy meet without any appointment. I witnessed the night of Al-`Aqaba (pledge) with Allah's Apostle when we pledged for Islam, and I would not exchange it for the Badr battle although the Badr battle is more popular amongst the people than it (i.e. Al-`Aqaba pledge). As for my news (in this battle of Tabuk), I had never been stronger or wealthier than I was when I remained behind the Prophet in that Ghazwa. By Allah, never had I two she-camels before, but I had then at the time of this Ghazwa. Whenever Allah's Apostle wanted to make a Ghazwa, he used to hide his intention by apparently referring to different Ghazwa till it was the time of that Ghazwa (of Tabuk) which Allah's Apostle fought in severe heat, facing, a long journey, desert, and the great number of enemy. So the Prophet announced to the Muslims clearly (their destination) so that they might get prepared for their Ghazwa. So he informed them clearly of the destination he was going to. Allah's Apostle was accompanied by a large number of Muslims who could not be listed in a book namely, a register." Ka`b added, "Any man who intended to be absent would think that the matter would remain hidden unless Allah revealed it through Divine Revelation. So Allah's Apostle fought that Ghazwa at the time when the fruits had ripened and the shade looked pleasant. Allah's Apostle and his companions prepared for the battle and I started to go out in order to get myself ready along with them, but I returned without doing anything. I would say to myself, 'I can do that.' So I kept on delaying it every now and then till the people got ready and Allah's Apostle and the Muslims along with him departed, and I had not prepared anything for my departure, and I said, I will prepare myself (for departure) one or two days after him, and then join them.' In the morning following their departure, I went out to get myself ready but returned ...