On the authority of Abu Hurayrah (may Allah be pleased with him) from the AProphet (may Allah be pleased with him), who said:
A prayer performed by someone who has not recited the Essence of the Qur'an during it is deficient (and he repeated the word three times), incomplete. Someone said to Abu Hurayrah [even though] we are behind the imamÉ He said: recite it to yourself, for I have heard the Prophet (may the blessings adn peace of Allah be upon him) say: Allah (mighty adn sublime be He), has said:
I have divided prayer between Myself and My servant into two halves, and My servant shall have what he has asked for. When the servant says: Al-hamdu lillahi rabbi l-alamin, Allah (mighty and sublime be He) says: My servant has praised Me. And when he says: Ar-rahmani'r-rahim, Allah (mighty and sublime be He) says: My servant has extolled Me, and when he says: Maliki yawmi'd-din, Allah says: My servant has glorified Me- and on one occasion He said: My servant has submitted to My power. And when he says: Iyyaka na'budu wa iyyaka nasta'in, He says: this is between Me and My servant, and My servant shall have what has asked for. And when he says: Ihdina s-sirata l-mustaqim, sirata lladhina anàmta alayhim ghayri l-maghdubi alayhim wa la d-dallin,He says: This is for My servant, adn My servant shall have what he has asked for.
It was related by Muslim (also by Malik at-Tirmidhi, Abu Dawud, an-Nasaì and Ibn Majah)