Musnad Ahmed: Hadith 3902

They were with Ibn Mas'ood (رضي الله عنه) when the time for prayer came. 'Alqarnah and al-Aswad were late, so Ibn Mas'ood took them by their hands and put one of them on his right and the other on his left, then they bowed and they put their hands on their knees. He smacked their bands, then he put his palms together and interlaced his fingers, and put (his hands) between his thighs. And he said: I saw the Prophet (ﷺ) do that.