Sunan Abi Dawud 903
سنن أبي داود#903SahihNarrated Abdullah ibn Umar: Sa'id ibn Ziyad ibn Subayh al-Hanafi said: I prayed by the side of Ibn Umar and I put my hands on my waist. When he finished his prayer, He said: This is a cross in prayer; the Messenger of Allah (ﷺ) used to forbid it
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 Lighairihi
Zubair Ali ZaiIsnaad Sahih
In-book reference: 2:513