It is narrated from Sayyiduna Jarir (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: "Whoever does not show mercy to people, Allah the Exalted does not show mercy to him."
Hadith Referenceالادب المفرد / كتاب الصغير / 370
Hadith Gradingالألبانی:صحيح
Hadith Takhrij«صحيح : أخرجه البخاري ، كتاب التوحيد : 7376 و مسلم كتاب الفضائل ، رقم : 2319»
Explanation & Benefits
Shaykh Maulana Usman Muneeb
Benefits and Issues: ➊ The point is that a person who does not deal with people with gentleness, compassion, and affection is not worthy that Allah, exalted is He, should have mercy on him in this world or the Hereafter. For whoever does not care for the helpless and destitute should not expect that when he himself is helpless and destitute, Allah, exalted is He, will have mercy on him. ➋ Its connection to the chapter heading is that calling out with "O my son" (yā bunayya) is among the acts of kindness and compassion.
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 370