Language:
كتاب السهو
22  
Forgetfulness in Prayer
(9)
Chapter: Beckoning during the Salat [by a person in Salat]
(9)
باب الإِشَارَةِ فِي الصَّلاَةِ
Sahih al-Bukhari 1235

Narrated Asma':

I went to `Aisha and she was standing praying and the people, too, were standing (praying). So I said, "What is the matter with the people?" She beckoned with her head towards the sky. I said, "(Is there) a sign?" She nodded intending to say, "Yes."

حَدَّثَنَا يَحْيَى بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنِي ابْنُ وَهْبٍ، حَدَّثَنَا الثَّوْرِيُّ، عَنْ هِشَامٍ، عَنْ فَاطِمَةَ، عَنْ أَسْمَاءَ، قَالَتْ دَخَلْتُ عَلَى عَائِشَةَ ـ رضى الله عنها ـ وَهِيَ تُصَلِّي قَائِمَةً وَالنَّاسُ قِيَامٌ فَقُلْتُ مَا شَأْنُ النَّاسِ فَأَشَارَتْ بِرَأْسِهَا إِلَى السَّمَاءِ‏.‏ فَقُلْتُ آيَةٌ‏.‏ فَقَالَتْ بِرَأْسِهَا أَىْ نَعَمْ‏.‏
Reference : Sahih al-Bukhari 1235
In-book reference : Book 22, Hadith 13
USC-MSA web (English) reference : Vol. 2, Book 22, Hadith 327
  (deprecated numbering scheme)