Part of Islamic Law
     This is proven from the three major sources of Islamic    law:           The Qur'an. Says Allah in the Qur'an, "O you who     believe, when you rise for prayer, wash your     faces and your hands up to the elbows and lightly     rub your heads and (wash) your feet up to the     ankles (al-Mai'dah 6).
           The Sunnah. Abu Hurairah reported that the     Messenger of Allah said, "Allah does not accept     the prayer of one who nullified his ablution     until he performs it again." (Related by     al-Bukhari, Muslim, Abu Dawud and at-Tirmidhi.)           The Consensus. There is a consensus of scholarly     opinion that ablution is part of Islamic law.
     Therefore, it is a recognized fact of the     religion.
      
Ablutions virtues
     Many hadith state the virtues of ablution. We shall    mention just a few:           'Abdullah ibn as-Sunnabiji stated that the     Messenger of Allah said, "When a slave makes     ablution and rinses his mouth, his wrong deeds     fall from it. As he rinses his nose, his wrong     deeds fall from it. When he washes his face, his     wrong deeds fall from it until they fall from     beneath his eyelashes. When he washes his hands,     his wrong deeds fall from them until they fall     from beneath his fingernails. When he wipes his     head, his wrong deeds fall from it until they     fall from his ears. When he washes his feet, his     wrong deeds fall from them until they fall from     beneath his toenails. Then his walking to the     mosque and his prayer give him extra reward."
     (Related by Malik, an-Nasa'i, Ibn Majah and     al-Hakim.)           Anas reported that the Messenger of Allah said,     "If good characteristics exist in a person, Allah     makes all of his acts good. If a person purifies     himself for prayer, he expiates all of his sins     and his prayer is considered an extra reward for     him." (Related by Abu Ya'la, al-Bazzar and     at-Tabarani in al-Ausat.)           Abu Hurairah reported that the Messenger of Allah     said, "'Shall I inform you (of an act) by which     Allah erases sins and raises degrees?" They said,     "Certainly, O Messenger of Allah." He said,     "Perfecting the ablution under difficult     circumstances, taking many steps to the mosque,     and waiting for the (next) prayer after the     (last) prayer has been performed. That is ribat.
     (Related by Malik, Muslim, at-Tirmidhi and     an-Nasa'i.)           Abu Hurairah also reported that the Messenger of     Allah, upon whom be peace, passed by a grave site     and said, "Peace be upon you, O home of believing     people. Allah willing, we shall meet you soon,     although I wish I could see my brothers." They     asked, "Are we not your brothers, O Messenger of     Allah?" He said, "You are my companions. My     brothers are the ones who will come after (us)."
     They said, "How will you know the people of our     nation who will come after you, O Messenger of     Allah?" He said, "If a man has a group of horses     with white forelocks amidst a group of horses     with black forelocks, will he recognize his     horses?" They said, "Certainly, O Messenger of     Allah." He said, "They (my brothers) will come     with white streaks from their ablutions, and I     will receive them at my cistern. But there will     be some who will be driven away from my cistern     as a stray camel is driven away. I will call them     to come. It will be said, 'They changed matters     after you,' then I will say, 'Be off, be off."'     (Related by Muslim.)      
We are identifying and building the related set of Ayahs for this Hadith. Please share your feedback and let us know if you identify any referencing issues.
"When a person dies, his works end, except for three: ongoing charity, knowledge that is benefited from, and a righteous child who prays for him."
Prophet Mohammed (PBUH)
"The best of what a man leaves behind are three: a righteous child who supplicates for him, ongoing charity the reward of which reaches him, and knowledge that is acted upon after him."
Sunan Ibn Mājah
"Every day two angels come down from Heaven and one of them says, 'O Allah! Compensate every person who spends in Your Cause,' and the other (angel) says, 'O Allah! Destroy every miser.'"
Sahih Bukhari