Mughira bin Shuba reported,

The Messenger of Allah ﷺ stayed behind to relieve himself. He then asked, "Do you have any water for purification?"So I followed him with a small water vessel containing water. He washed his hands and face, then went to roll up his sleeves, but the sleeves of the cloak on my arms were tight, so he pulled his hands out from beneath the cloak and washed his forearms. Then he wiped over his turban and leather socks, mounted his ride, and I mounted mine.We caught up with the people, and Abdul-Rahman bin Awf had already led them in one rakah of prayer. When he sensed the Prophet's ﷺ presence, he began to step back, but the Prophet ﷺ gestured to him to complete the prayer and said, "You have done well. Continue doing so."

Ahmad 18172

Sahih

حدثنا محمد بن أبي عدي عن حميد عن بكر

عن حمزة بن المغيرة بن شعبة عن أبيه قال

تخلف رسول الله ﷺ فقضى حاجته فقال هل معك طهور قال فاتبعته بميضأة فيها ماء فغسل كفيه ووجهه ثم ذهب يحسر عن ذراعيه وكان في يدي الجبة ضيق فأخرج يديه من تحت الجبة فغسل ذراعيه ثم مسح على عمامته وخفيه وركب وركبت راحلتي فانتهينا إلى القوم وقد صلى بهم عبد الرحمن بن عوف ركعة فلما أحس بالنبي ﷺ ذهب يتأخر فأومأ إليه أن يتم الصلاة وقال قد أحسنت كذلك فافعل

أحمد 18172صحيح
Contents
Reference
Commentary
Ayat
Collection
Musnad Ahmad
Book
Mughira bin Shuba
Numbering
Darussalam 18172
Ahmad 18172