Sunan an-Nasa'i 1941
سنن النسائي#1941Sahihأَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا خَالِدٌ، قَالَ حَدَّثَنَا أَشْعَثُ، عَنِ الْحَسَنِ، عَنْ عَبْدِ اللَّهِ بْنِ الْمُغَفَّلِ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ تَبِعَ جَنَازَةً حَتَّى يُفْرَغَ مِنْهَا فَلَهُ قِيرَاطَانِ فَإِنْ رَجَعَ قَبْلَ أَنْ يُفْرَغَ مِنْهَا فَلَهُ قِيرَاطٌ " .
It was narrated that 'Abdullah bin Al-Mughaffal said:"The Messenger of Allah said: 'Whoever follows a Janazah until it is finished, he will have two Qirats, and whoever goes back before it is finished, he will have one Qirat
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: 21:124