Lady Aisha Siddiqa (may Allah be pleased with her) narrates: A man sought permission to enter upon the Prophet Muhammad (peace be upon him). The Prophet (peace be upon him) said: Allow him to enter, he is a very bad person of his family (the narrator is doubtful about one word here). When that person entered, the Prophet (peace be upon him) spoke to him gently. When he left, I asked, O Messenger of Allah (peace be upon him)! You had said this about him before, yet you spoke to him gently. The Prophet (peace be upon him) said: O Aisha, in the sight of Allah, the worst person among the people will be the one whom people leave alone (ignore) to avoid his evil (the narrator is doubtful about one word here).
Hadith Referenceصحیح ابن حبان / كتاب السير / 4538
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط البخاري