Mishkat al-Masabih
Mishkat al-Masabih 2253
Arabic hadith text
وَعَنْ أَنَسٍ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَرْفَعُ يَدَيْهِ فِي الدُّعَاءِ حَتَّى يُرى بياضُ إبطَيْهِ
Translation
Anas reported: The Messenger of God (peace be upon him) used to raise his hands in supplication until the whiteness of his armpits could be seen. The Arabic source marks it as not studied by al-Albani.