صحيح مسلم

Busr b Sa'id reported that Zaid b Khalid al-Juhani sent him to Abu Juhaim in order to ask him what he had heard from the Messenger of Allah (ﷺ) with regard to the passer in front of the worshipper. Abu Juhaim reported that the Messenger of Allah (ﷺ) said: If anyone who passes in front of a man who is praying knew the responsibility he incurs, he would stand still forty (years) rather than to pass in front of him Abu Nadr said: I do not know whether he said forty days or months or years.