Musnad Ahmad 5:207

Yahya ibn Adam narrated to us, Isra'il narrated to us, from Abu Ishaq, from Hani ibn Hani, from Ali, who said: When al-Hasan was born, I named him Harb. The Messenger of Allah (peace and blessings of Allah be upon him) came and said: "Show me my son. What have you named him?" I said: "Harb." He said: "Rather, he is Hasan." When al-Husayn was born, I named him Harb. The Messenger of Allah (peace and blessings of Allah be upon him) came and said: "Show me my son. What have you named him?" I said: "Harb." He said: "Rather, he is Husayn." When the third was born, I named him Harb. The Prophet (peace and blessings of Allah be upon him) came and said: "Show me my son. What have you named him?" I said: "Harb." He said: "Rather, he is Muhsin." Then he said: "I have named them after the names of the sons of Aaron: Shabar, Shabir, and Mushabir."