Abdullah ibn Mas'ud said: Should I not pray for you the way the Messenger of Allah (ﷺ) prayed? So he prayed, raising his hands only once.

Abu Dawud said: This is a summarized version of a longer narration and it is not authentic with this wording.
Sunan Abi Dawud Book 2, Hadith 358
← Previous Hadith The Messenger of Allah (ﷺ) taught us how to pray. He then uttered the takbir (Allah is most great) and raised his hands; when he bowed, he joined his hands and placed them between his knees. When this (report) reached Sa'd, he said: My brother said truly. We used to do this; then we were later on commanded to do this, that is, to place the hands on the knees.

Sunan Abi Dawud Book 2, Hadith 357 Next Hadith → He raised his hands once in the beginning. Some narrated: (raised his hands) once only.

Sunan Abi Dawud Book 2, Hadith 359