´It was narrated from Abul-Ahwas 'Awf bin Malik Al- Jushami that his father said:` "I said: 'O Messenger of Allah, my cousin comes to me and I swear that I will not give him anything or uphold the ties of kinship with him.' He said: 'Offer expiation for what you swore about.'"
Hadith Referenceسنن ابن ماجه / كتاب الكفارات / 2109
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:إسناده صحيح
1؎: That is, maintain the ties of kinship with her, and this is a better deed than fulfilling the oath; therefore, break the oath and offer its expiation.
´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."
Hafiz Muhammad Ameen
1) In this hadith, encouragement towards ihsan (excellence in conduct) has been given, that if someone does evil to another, then the latter should respond to the evildoer with gentleness.
2) If someone has sworn an oath to sever ties of kinship (qat‘ al-rahm), then he will give its expiation (kaffarah) and will maintain the ties of kinship (silat al-rahm).
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 3819