Sayyiduna Ali (may Allah be pleased with him) said: When Sayyiduna al-Hasan bin Ali (may Allah be pleased with him) was born, the Messenger of Allah (peace and blessings be upon him) came and said: "Show me my son. What have you named him?" I said: I have named him Harb. He said: "No, rather he is Hasan." Then when Sayyiduna al-Husayn bin Ali (may Allah be pleased with him) was born, he (peace and blessings be upon him) came and said the same thing. I said: I have named him Harb. He said: "No, rather he is Husayn." Then when Sayyidah Fatimah gave birth to the third son, he (peace and blessings be upon him) came and said the same thing. I said: I have named him Harb. He said: "No, rather he is Muhassin." Then he said: "I have named them after the names of the children of Harun (peace be upon him): Shabbar, Shubayr and Mushabbir."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2761