Musnad Ahmad 962:118

'Abd al-Rahman ibn Mahdi narrated to us, from Mu'awiyah ibn Salih, from al-Safar ibn Nusayr, from Yazid ibn Shurayh, that he heard Abu Umamah narrating that the Messenger of Allah (peace and blessings of Allah be upon him) said: "None of you should come to the prayer while he is suppressing the urge to urinate, nor should he single himself out for something to the exclusion of his companions, nor should he cast his eyes into a house until he has asked for permission." A sheikh said when Yazid narrated this to him: "I heard Abu Umamah narrating this hadith."