Yahya related to me from Malik from Abu'z Zinad from al-Araj from Abu Hurayra that the Messenger of Allah, may Allah bless him and grant him peace, said, "The angels ask for blessings on each one of you as long as he is in the place where he has prayed and has not discharged anything. They say, 'Allah, forgive him. Allah have mercy on him.' "
USC-MSA web (English) reference: Book 9, Hadith 54
Arabic reference: Book 9, Hadith 385