Muwatta Malik 364
موطأ مالك#364SahihThese are the words of a Successor — the generation after the Companions — not of the Prophet ﷺ.
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ عَطَاءِ بْنِ يَسَارٍ، أَنَّ كَعْبَ الأَحْبَارِ، قَالَ لَوْ يَعْلَمُ الْمَارُّ بَيْنَ يَدَىِ الْمُصَلِّي مَاذَا عَلَيْهِ لَكَانَ أَنْ يُخْسَفَ بِهِ خَيْرًا لَهُ مِنْ أَنْ يَمُرَّ بَيْنَ يَدَيْهِ .
Yahya related to me from Malik from Zayd ibn Aslam from Ata ibn Yasar that Kab al-Ahbar said, "If the person who passed in front of a man praying knew what he was bringing on himself, it would be better for him to sink into the ground than to pass in front of him
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 9:39