Anas bin Malik reported,

Anas reported that the Prophet ﷺ would not raise his hands in any of his supplications except during the prayer for rain, when he would raise them so high that the whiteness of his armpits became visible.

Azami 10888

Sahih

عن أنس بن مالك

قال كان النبي ﷺ لا يرفع يديه في شيء من دعائه إلا في الاستسقاء، وإنه يرفع يديه حتى يرى بياض إبطيه.

الأعظمي 10888صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Supplications, remembrances, and prayer upon the chosen Prophet ﷺ
Chapter
Etiquette of supplication
Section
Raising the hands in the rain prayer and doing so extensively
Numbering
Jami al-Kamil 10888 (2nd edition)
Azami 10888