Verse from Al'Quran
O men! Here is a parable set forth! listen to it! Those on whom, besides Allah, ye call, cannot create (even) a fly, if they all met together for the purpose! and if the fly should snatch away anything from them, they would have no power to release it from the fly. Feeble are those who petition and those whom they petition!
The Qur’an 22/73
Verse from Hadith
Three prayers will be accepted certainly: Opressed one’s prayer, guest’s prayer and prayer of father for his child.
Ibn Mâjah, Duâ, 11.