Zayd bin Khalid al-Juhani sent him to Abu Juhaym to ask what he had heard from the Messenger of Allah ﷺ regarding one who passes in front of a person praying.Abu Juhaym said, "The Messenger of Allah ﷺ said, 'If the one who passes in front of a person praying knew what was upon him, standing still for forty would be better for him than passing in front of him.'"Abu Nadr said, "I do not know whether he said forty days, forty months, or forty years."
حدثنا القعنبي عن مالك عن أبي النضر مولى عمر بن عبيد الله
أن زيد بن خالد الجهني أرسله إلى أبي جهيم يسأله ماذا سمع من رسول الله ﷺ في المار بين يدي المصلي فقال أبو جهيم قال رسول الله ﷺ لو يعلم المار بين يدي المصلي ماذا عليه لكان أن يقف أربعين خير له من أن يمر بين يديه قال أبو النضر لا أدري قال أربعين يوما أو شهرا أو سنة
Bukhari narrated it, Prayer, chapter on the sin of one who passes in front of a person praying, no. 510, and Muslim, Prayer, chapter on preventing one who passes in front of a person praying, no. 507, from the hadith of Malik through this route, and it is found in Muwatta (Yahya): 1/154, 155.