Sunan Abi Dawud 958
سنن أبي داود#958Sahihحَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، عَنْ مَالِكٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ الْقَاسِمِ، عَنْ عَبْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، قَالَ سُنَّةُ الصَّلاَةِ أَنْ تَنْصِبَ، رِجْلَكَ الْيُمْنَى وَتَثْنِيَ رِجْلَكَ الْيُسْرَى .
Abdullah bin 'Umar said:"A Sunnah of the prayer is that you should raise your right foot, and make your left foot lie (on the ground)
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:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih Bukhari (827)
In-book reference: 2:569