Sahih Al Bukhari Hadith Number 1502

Narrated Anas bin Malik: I took `Abdullah bin Abu Talha to Allah’s Messenger (peace be upon him) to perform Tahnik for him. (Tahnik was a custom among the Muslims that whenever a child was born they used to take it to the Prophet (peace eb upon him) who would chew a piece of date and put a part of its juice in the child’s mouth). I saw the Prophet (peace be upon him) and he had an instrument for branding in his hands and was branding the camels of Zakat.