Sa'id bin al-Musayyib (may Allah have mercy on him) narrates from his father, and he from his grandfather (may Allah be pleased with them both), that the Messenger of Allah (peace and blessings be upon him) asked: "What is your name?" I said: "Hazn" (rough). He (peace and blessings be upon him) said: "No, rather you are 'Sahl' (easy)." He said: I will not change a name my father gave me. Ibn al-Musayyib (may Allah have mercy on him) said: After that, hardship remained among us.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19315