Ablutions (Wudu') 
Bukhari :: Book 1 :: Volume 4 :: Hadith 212
Narrated Anas:
The Prophet said, "If anyone of you feels drowsy while praying, he should sleep till he understands what he is saying (reciting)."
Ablutions (Wudu')
Bukhari :: Book 1 :: Volume 4 :: Hadith 212
Narrated Anas:
The Prophet said, "If anyone of you feels drowsy while praying, he should sleep till he understands what he is saying (reciting)."