Sahih Al Bukhari Hadith Number 860

Narrated Anas bin Malik: My grandmother Mulaika invited Allah’s Messenger (peace be upon him) for a meal which she had prepared specially for him. He ate some of it and said, “Get up. I shall lead you in the prayer.” I brought a mat that had become black owing to excessive use and I sprinkled water on it. Allah’s Messenger (peace be upon him) stood on it and prayed two rak`at; and the orphan was with me (in the first row), and the old lady stood behind us.

10  Call to Prayers (Adhaan)
Hadith number 860
Volume no 1
Chapter: 161 (The ablution for boys (youngsters). When they should perform Ghusl (take a bath) and Tuhur (purification). Their attendance at congregational prayers and their rows in the prayers.)