أَخْبَرَنَا سُلَيْمَانُ بْنُ دَاوُدَ، قَالَ أَنْبَأَنَا ابْنُ وَهْبٍ، عَنْ يُونُسَ، قَالَ قَالَ ابْنُ شِهَابٍ فَأَخْبَرَنِي عَبْدُ الرَّحْمَنِ بْنُ كَعْبِ بْنِ مَالِكٍ، أَنَّ عَبْدَ اللَّهِ بْنَ كَعْبٍ، قَالَ سَمِعْتُ كَعْبَ بْنَ مَالِكٍ، يُحَدِّثُ حَدِيثَهُ حِينَ تَخَلَّفَ عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي غَزْوَةِ تَبُوكَ قَالَ فَلَمَّا جَلَسْتُ بَيْنَ يَدَيْهِ قُلْتُ يَا رَسُولَ اللَّهِ إِنَّ مِنْ تَوْبَتِي أَنْ أَنْخَلِعَ مِنْ مَالِي صَدَقَةً إِلَى اللَّهِ وَإِلَى رَسُولِهِ ‏.‏ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ أَمْسِكْ عَلَيْكَ بَعْضَ مَالِكَ فَهُوَ خَيْرٌ لَكَ ‏"‏ ‏.‏ فَقُلْتُ فَإِنِّي أُمْسِكُ سَهْمِي الَّذِي بِخَيْبَرَ ‏.‏ مُخْتَصَرٌ ‏.‏

'Abdur-Rahman bin Ka'b bin Malik narrated that 'Abdullah bin Ka'b said: "I heard Ka'b bin Malik narrating his Hadith about when he stayed behind and did not join the Messenger of Allah on the campaign to Tabuk. He said: 'When I sat down before him I said: "O Messenger of Allah, as part of my repentance I want to give my wealth in charity to Allah and His Messenger." The Messenger of Allah said: "Keep some of your wealth for yourself; that is better for you." I said: "I will keep my share that is in Khaibar."'" Translation Not Available

Book Ref: Sunan An Nisai Book 35 Hadith 3824
Web Ref:  Sunan An Nisai Vol 4 Book 35 Hadith 3855