Sunan Abi Dawud 1969
سنن أبي داود#1969Sahihحَدَّثَنَا الْقَعْنَبِيُّ، حَدَّثَنَا عَبْدُ اللَّهِ، - يَعْنِي ابْنَ عُمَرَ - عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّهُ كَانَ يَأْتِي الْجِمَارَ فِي الأَيَّامِ الثَّلاَثَةِ بَعْدَ يَوْمِ النَّحْرِ مَاشِيًا ذَاهِبًا وَرَاجِعًا وَيُخْبِرُ أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَفْعَلُ ذَلِكَ .
Nafi' reported on the authority of Ibn Umar. He (ibn Umar) used to come (to Mina) and threw pebbles three days after the day of sacrifice walking when arriving and returning (both ways). He reported that the Prophet (ﷺ) used to do so
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: 11:249