Maliks Muwatta Book 9, Hadith Number 60.

Section : Waiting for The Prayer and Walking to It.

Yahya related to me from Malik from Amir ibn Abdullah ibn az-Zubayr from Amr ibn Sulaymaz-Zuraqi from Abu Qatadaal-Ansari that the Messenger of Allah, may Allah bless him and grant him peace, said, “When you enter the mosque, you should pray two rakas before you sit down.”