Sunan Ibn Majah — The Book On The Mosques And The Congregations — Hadith No: 784
Translation
It was narrated that Anas said:"Banu Salimah wanted to move from their homes to somewhere near the mosque, but the Prophet did not want the outskirts of Al-madinah to be left vacant, so he said: 'O Banu Salimah, do you not hope for the reward of your footsteps?' So they stayed (where they were)