Hadith 1111:15
Yahya and Abd al-Rahman narrated to us, from Sufyan, from Asim ibn Ubayd Allah, from Ubayd Allah ibn Abi Rafi, from his father, who said: I saw the Messenger of Allah, may Allah bless him and grant him peace, call the adhan in the ear of al-Hasan when Fatimah gave birth to him, [the adhan] for prayer.
حدثنا يحيى، وعبد الرحمن، عن سفيان، عن عاصم بن عبيد الله، عن عبيد الله بن أبي رافع، عن أبيه، قال: رأيت رسول الله صلى الله عليه وسلم " أذن في أذني الحسن حين ولدته فاطمة بالصلاة "