آداب الدعاء
‘Umar (may Allah be pleased with him) reported: Whenever the Messenger of Allah (may Allah's peace and blessings be upon him) stretched out his hands in supplication, he would not put them down until he had wiped his face with them.  
عن عمر -رضي الله عنه- قال: كان رسول الله -صلى الله عليه وسلم- إذا مَدَّ يَدَيْهِ في الدُّعاءِ، لمْ يَرُدَّهُمَا حَتَى يَمَسَحَ بِهِمَا وَجْهَهُ.

شرح الحديث :


This Hadīth clearly indicates that it is permissible for one to wipe his face with his hands when he is done with supplication. The reason behind that, and Allah knows best, is that since Allah, Glorified and Exalted, does not turn down His slave's hands (raised in supplication), it could be said that his hands receive mercy by the blessing of supplication. Thus, it is good to let such mercy flow upon the face as well, because the face is the noblest among the body organs and the worthiest of honor.  

ترجمة نص هذا الحديث متوفرة باللغات التالية