Abu Hurairah (May Allah be pleased with him) reported:
A man said to Messenger of Allah (ﷺ): "I have relatives with whom I try to maintain good relationship but they sever relations with me; whom I treat kindly but they treat me badly, with whom I am gentle but they are rough to me." He (ﷺ) replied, "If you are as you have said, then it is as though you are feeding them hot ashes and you will not be without a supporter against them from Allah, as long as you do so."[Muslim].
Arabic/English book reference: Book 1, Hadith 648