Sayyidah Aishah (may Allah be pleased with her) said that a man asked permission to enter upon the Prophet (peace and blessings be upon him). He (peace and blessings be upon him) said: "Give him permission, though he is the worst man of his clan." When he came in, he (peace and blessings be upon him) spoke gently to him. Sayyidah Aishah (may Allah be pleased with her) said: O Prophet of Allah (peace and blessings be upon him), you spoke of him in that way, and then you spoke gently to him? He (peace and blessings be upon him) said: "O Aishah (may Allah be pleased with her), the person of the worst standing among people on the Day of Resurrection will be the one who is left alone because of his obscene speech."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 21150