Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Do not laugh too much, for excessive laughter deadens the heart."

It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Who is there who will learn these words from me, act upon them himself, or teach them to someone who will act upon them?" Sayyiduna Abu Hurairah (may Allah be pleased with him) said: O Messenger of Allah! I am (willing). So the Prophet (peace and blessings be upon him) took my hand and, counting, mentioned five things. He said: "Avoid what Allah has forbidden, you will become the greatest worshipper among the people. Be content with what Allah has allotted for you, you will become the richest of people. Treat your neighbor well, you will become a believer. Love for people what you love for yourself, you will become a Muslim. And refrain from excessive laughter, for too much laughter deadens the heart."