Sunan an-Nasai Book 35, Hadith 3788

أَخْبَرَنَا مُحَمَّدُ بْنُ مَنْصُورٍ، عَنْ سُفْيَانَ، قَالَ حَدَّثَنَا أَبُو الزَّعْرَاءِ، عَنْ عَمِّهِ أَبِي الأَحْوَصِ، عَنْ أَبِيهِ، قَالَ قُلْتُ يَا رَسُولَ اللَّهِ أَرَأَيْتَ ابْنَ عَمٍّ لِي أَتَيْتُهُ أَسْأَلُهُ فَلاَ يُعْطِينِي وَلاَ يَصِلُنِي ثُمَّ يَحْتَاجُ إِلَىَّ فَيَأْتِينِي فَيَسْأَلُنِي وَقَدْ حَلَفْتُ أَنْ لاَ أُعْطِيَهُ وَلاَ أَصِلَهُ فَأَمَرَنِي أَنْ آتِيَ الَّذِي هُوَ خَيْرٌ وَأُكَفِّرَ عَنْ يَمِينِي ‏.‏

It was narrated from Abu Al-Ahwas that his father said:"I said: 'O Messenger of Allah, I have a cousin, and I come to him and ask him (for help) but he does not give me anything, and he does not uphold the ties of kinship with me. Then, when he needs me, he comes to me and asks me (for help). I swore that I would not give him anything, nor uphold the ties of kinship with him.' He commanded me to do that which is better and to offer expiation for my oath