Sahih al-Bukhari, Book 93, Hadith 84 (In-Book) ⓘ

Narrated `Abdullah bin Ka`b bin Malik: Who was Ka`b's guide from among his sons when Ka`b became blind: I heard Ka`b bin Malik saying, "When some people remained behind and did not join Allah's Messenger in the battle of Tabuk.." and then he described the whole narration and said, "Allah's Messenger forbade the Muslims to speak to us, and so we (I and my companions) stayed fifty nights in that state, and then Allah's Messenger announced Allah's acceptance of our repentance."

حَدَّثَنِي يَحْيَى بْنُ بُكَيْرٍ، حَدَّثَنَا اللَّيْثُ، عَنْ عُقَيْلٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَبْدِ اللَّهِ بْنِ كَعْبِ بْنِ مَالِكٍ، أَنَّ عَبْدَ اللَّهِ بْنَ كَعْبِ بْنِ مَالِكٍ ـ وَكَانَ قَائِدَ كَعْبٍ مِنْ بَنِيهِ حِينَ عَمِيَ ـ قَالَ سَمِعْتُ كَعْبَ بْنَ مَالِكٍ، قَالَ لَمَّا تَخَلَّفَ عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي غَزْوَةِ تَبُوكَ ـ فَذَكَرَ حَدِيثَهُ ـ وَنَهَى رَسُولُ اللَّهِ صلى الله عليه وسلم الْمُسْلِمِينَ عَنْ كَلاَمِنَا، فَلَبِثْنَا عَلَى ذَلِكَ خَمْسِينَ لَيْلَةً، وَآذَنَ رَسُولُ اللَّهِ صلى الله عليه وسلم بِتَوْبَةِ اللَّهِ عَلَيْنَا‏.‏