Hadith
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يُصَلِّي فِي مَسْجِدِ ذِي الْحُلَيْفَةِ
Yahya related to me from Malik from Nafi that Abdullah ibn Umar used to pray in the mosque of Dhu'l-Hulayfa, and then go outside and get on his camel and when his camel had stood up he would begin to do talbiya
Sahih · Salim al-Hilali
Muwatta Malik 737 ·Book 20, Hadith 33·Also available on sunnah.com·