It was narrated from Anas bin Malik that the Prophet (ﷺ) did not raise his hands in any of his supplications except when praying for rain (Istisqa’), when he raised his hands so high that the whiteness of his armpits could be seen.
حَدَّثَنَا نَصْرُ بْنُ عَلِيٍّ الْجَهْضَمِيُّ، حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ، حَدَّثَنَا سَعِيدُ بْنُ أَبِي عَرُوبَةَ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، أَنَّ نَبِيَّ اللَّهِ ـ صلى الله عليه وسلم ـ كَانَ لاَ يَرْفَعُ يَدَيْهِ فِي شَىْءٍ مِنْ دُعَائِهِ إِلاَّ عِنْدَ الاِسْتِسْقَاءِ فَإِنَّهُ كَانَ يَرْفَعُ يَدَيْهِ حَتَّى يُرَى بَيَاضُ إِبْطَيْهِ .
IbnMaja
Establishing the Prayer and the Sunnah Regarding Them • Hadith 1180