"The Prophet ﷺ would not raise his hands in any of his supplications except when praying for rain (Al-Istisqa')." (One of the narrators) Shu'bah said: "I said to Thabit: 'Did you hear it from Anas?' He said: 'Subhan Allah!' I said: 'Did you hear it?' He said: 'Subhan Allah!' (Using translation from Nasāʾī 1748)   

كَانَ النَّبِيُّ ﷺ «لَا يَرْفَعُ يَدَيْهِ فِي شَيْءٍ مِنْ دُعَائِهِ إِلَّا فِي الِاسْتِسْقَاءِ» قَالَ شُعْبَةُ فَقُلْتُ لِثَابِتٍ أَنْتَ سَمِعْتَهُ مِنْ أَنَسٍ؟ قَالَ سُبْحَانَ اللهِ قُلْتُ أَنْتَ سَمِعْتَهُ مِنْ أَنَسٍ؟ قَالَ سُبْحَانَ اللهِ خَالَفَهُ وَهْبُ بْنُ جَرِيرٍ  

[Machine] The Messenger of Allah ﷺ used to raise his hands in supplication until the whiteness of his armpits was visible. Shu'bah said, "So I went to 'Ali bin Zaid and mentioned this to him, and he said, 'He only did that for seeking rain.' So I said to him, 'Did you hear it from Anas?' He said, 'Subhan Allah!' I said, 'Did you hear it from Anas?' He said, 'Subhan Allah!' Abu 'Abdullah (al-Bukhari) said: And this Hadith has been narrated from Qatadah from Anas."  

أَنَّ رَسُولَ اللهِ ﷺ كَانَ «يَرْفَعُ يَدَيْهِ فِي الدُّعَاءِ حَتَّى يُرَى بَيَاضُ إِبْطَيْهِ» قَالَ شُعْبَةُ فَأَتَيْتُ عَلِيَّ بْنَ زَيْدٍ فَذَكَرْتُ لَهُ ذَلِكَ فَقَالَ إِنَّمَا يُرِيدُ فِي الِاسْتِسْقَاءِ فَقُلْتُ لَهُ أَسَمِعْتَهُ مِنْ أَنَسٍ؟ قَالَ سُبْحَانَ اللهِ قُلْتُ أَسَمِعْتَهُ مِنْ أَنَسٍ؟ قَالَ سُبْحَانَ اللهِ قَالَ أَبُو عَبْدِ الرَّحْمَنِ وَقَدْ رَوَى هَذَا الْحَدِيثَ قَتَادَةُ عَنْ أَنَسٍ  

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. (Using translation from Ibn Mājah 1180)  

أَنَّ نَبِيَّ اللهِ ﷺ كَانَ «لَا يَرْفَعُ يَدَيْهِ فِي شَيْءٍ مِنْ دُعَائِهِ إِلَّا عِنْدَ الِاسْتِسْقَاءَ فَإِنَّهُ كَانَ يَرْفَعُ يَدَيْهِ حَتَّى يُرَى بَيَاضُ إِبْطَيْهِ»