Sunan Ibn Majah, Volume 2, Book 5, Hadith 944 (DarusSalam) ⓘ
Busr bin Sa’eed said: “They sent me to Zaid bin Khalid to ask him about passing in front of one who is performing prayer. He told me that the Prophet said: ‘Waiting for forty is better than passing in front of one who is performing prayer.’” (One of the narrators) Sufyan said: "I do not know if he meant forty years, months, days, or hours."
حَدَّثَنَا هِشَامُ بْنُ عَمَّارٍ، حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ سَالِمٍ أَبِي النَّضْرِ، عَنْ بُسْرِ بْنِ سَعِيدٍ، قَالَ أَرْسَلُونِي إِلَى زَيْدِ بْنِ خَالِدٍ أَسْأَلُهُ عَنِ الْمُرُورِ، بَيْنَ يَدَىِ الْمُصَلِّي فَأَخْبَرَنِي عَنِ النَّبِيِّ ـ صلى الله عليه وسلم ـ قَالَ " لأَنْ يَقُومَ أَرْبَعِينَ خَيْرٌ لَهُ مِنْ أَنْ يَمُرَّ بَيْنَ يَدَيْهِ " . قَالَ سُفْيَانُ فَلاَ أَدْرِي أَرْبَعِينَ سَنَةً أَوْ شَهْرًا أَوْ صَبَاحًا أَوْ سَاعَةً .
also referenced under: Hadith 944 (Reference) & Book 5, Hadith 997 (In-Book)