Musannaf Ibn Abi Shayba 28:889

Ibn Mahdi narrated to us, from Sufyan, from Ibrahim ibn al-Muhajir, from Mujahid, that Abu Sufyan sought to negotiate safety with al-Hasan and al-Husayn while they were young. He said: And Sufyan said, "The safety [granted by] a young person is not permissible."