Sayyiduna Uqbah bin Amir (may Allah be pleased with him) said: I heard the Prophet (peace and blessings be upon him) say: "Whoever performs ablution (wudu) and performs ablution well, then prays a prayer in which he remains attentive until he completes it, comes out of his sins as he was on the day his mother gave birth to him."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15008