"What did you hear from the Messenger of Allah ﷺ concerning a man passing in front of another while he is praying?"He replied, "I heard the Prophet ﷺ say, 'If any of you knew what is held against him for passing in front of his brother while he is praying, standing still for forty would be better for him than that.'"The narrator said, "I do not know whether he said forty years, forty months, or forty days."
حدثنا علي بن محمد حدثنا وكيع حدثنا سفيان عن سالم أبي النضر عن بسر بن سعيد أن زيد بن خالد أرسل إلى
ما سمعت من رسول الله ﷺ في الرجل يمر بين يدي الرجل وهو يصلي فقال سمعت النبي ﷺ يقول لو يعلم أحدكم ما له أن يمر بين يدي أخيه وهو يصلي كان لأن يقف أربعين قال لا أدري أربعين عاما أو أربعين شهرا أو أربعين يوما خير له من ذلك
Reported by Bukhari, Prayer, Chapter: "The sin of one who passes in front of a person praying," no. 510, and Muslim, Prayer, Chapter: "Preventing one who passes in front of a person praying," no. 507, from the hadith of Abu Nadr, through this same chain.