Sunan Abi Dawud 959
سنن أبي داود#959Sahih(There is another chain) reported from Yahya who said:"I heard Al-Qasim saying: "Abdullah bin 'Abdullah informed me that he heard 'Abdullah bin 'Umar saying: "From the Sunnah of the prayer is to lay your left foot on the ground, and raise your right foot
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih
In-book reference: 2:570