It is narrated from Sayyiduna Mughirah bin Shu'bah (may Allah be pleased with him); he said: The Messenger of Allah (peace and blessings be upon him) moved aside, and I moved aside with him (peace and blessings be upon him). I came close to him (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Do you have water with you?" I said: Yes. So he (peace and blessings be upon him) washed his palms and his face, then began to wash his arms, but the sleeve of the jubbah (cloak) he (peace and blessings be upon him) was wearing was tight, so he (peace and blessings be upon him) brought his hand out from under the jubbah and washed it, then wiped over his leather socks. Then he (peace and blessings be upon him) came to pray while Abdur-Rahman bin Awf (may Allah be pleased with him) was leading the people in prayer. When they saw the Prophet (peace and blessings be upon him), they cleared their throats (to signal), and he began to step back, but he (peace and blessings be upon him) gestured to him: "Carry on."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 18174