Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Indeed the act of obedience that (earns its reward) most quickly is maintaining the ties of kinship. The people of a household may be sinners, yet when they maintain the ties of kinship, their wealth grows and their numbers increase."
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains a narrator, Abu al-Dahma' al-Nasri, who is very weak (da'if jiddan).