“I was sitting in the presence of abu ‘Abd Allah (a.s.), when Najiyyah abu Habib asked the Imam saying, ‘May Allah keep my soul in service for your cause, I have a flour-mill. During the night I wake up (for Salah (prayer)) and notice from the mill that the servant is gone to sleep. (Can) I then knock at the wall to wake him up?’ The Imam replied, ‘Yes, you are in the condition of obeying Allah, the Most Majestic, the Most Glorious, when you are seeking to make a living.’” (Please consult a fatwa also.)