Sahih Bukhari
Call to Prayers (Adhaan)
Volume: 001 / Book Number: 011 / Hadith Number: 675
Narrated 'Abdullah bin 'Abi Qatada:
My father said, "The Prophet said, 'When I stand for prayer, I intend to prolong it but on hearing the cries of a child, I cut it short, as I dislike to trouble the child's mother.' "