Sunan an-Nasa'i, Volume 2, Book 13, Hadith 1271 (DarusSalam) ⓘ
It was narrated from Abdullah bin Az-Zubair: That the Prophet used to point with his finger when he supplicated, but he did not move it. Ibn Jurayj said: "And 'Amr added: 'Amir bin 'Abdullah bin Az-Zubair told me that his father saw the Prophet supplicating like that, putting his weight on his left arm, leaning on his left leg.'"
أَخْبَرَنَا أَيُّوبُ بْنُ مُحَمَّدٍ الْوَزَّانُ، قَالَ حَدَّثَنَا حَجَّاجٌ، قَالَ ابْنُ جُرَيْجٍ أَخْبَرَنِي زِيَادٌ، عَنْ مُحَمَّدِ بْنِ عَجْلاَنَ، عَنْ عَامِرِ بْنِ عَبْدِ اللَّهِ بْنِ الزُّبَيْرِ، عَنْ عَبْدِ اللَّهِ بْنِ الزُّبَيْرِ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يُشِيرُ بِأُصْبُعِهِ إِذَا دَعَا وَلاَ يُحَرِّكُهَا . قَالَ ابْنُ جُرَيْجٍ وَزَادَ عَمْرٌو قَالَ أَخْبَرَنِي عَامِرُ بْنُ عَبْدِ اللَّهِ بْنِ الزُّبَيْرِ عَنْ أَبِيهِ أَنَّهُ رَأَى النَّبِيَّ صلى الله عليه وسلم يَدْعُو كَذَلِكَ وَيَتَحَامَلُ بِيَدِهِ الْيُسْرَى عَلَى رِجْلِهِ الْيُسْرَى .
also referenced under: Hadith 1270 (Reference) & Book 13, Hadith 92 (In-Book)