Muwatta Malik 734
موطأ مالك#734Sahihوَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُصَلِّي فِي مَسْجِدِ ذِي الْحُلَيْفَةِ رَكْعَتَيْنِ فَإِذَا اسْتَوَتْ بِهِ رَاحِلَتُهُ أَهَلَّ .
Yahya related to me from Malik from Hisham ibn Urwa from his father that the Messenger of Allah, may Allah bless him and grant him peace, used to pray two rakas in the mosque at Dhu'l-Hulayfa, and then, when he had got on to his camel and it had stood up, he would begin doing talbiya
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:
In-book reference: 20:30