Salat is the most important of all forms of worship.  It is, in fact, the first and foremost item to be reckoned with on the Day of Judgment. The Prophet (Sallallaho alaihe wasallam) is reported to have said :

"Salaat is the only line of demarcation between Kufr and Islam."

Blessings of Nafl (non-obligatory) Prayers :

The Prophet (Sallallaho alaihe wasallam) reported that Allah told him :

"My wrath descends upon a person who bears ill-will towards my friends. And only those are blessed with My love who implicitly carry out Fardh (obligatory) injunctions. A person keeps on advancing in my esteem  through 'Nafl'; till I choose him as 'My beloved'. I then become his ear by which he listens, his eye by which he looks, his hands by which he holds, and his feet by which he walks (i.e. his listening, looking holding and walking are all in perfect accord with My injunctions, and he would never even dream of employing any part of his body in any action contrary to My commands). If such a person prays for anything, I grant it to him and if he seeks My protection I do protect him."

Those people are really blessed who, after performing their Fardh, are in the habit of observing Nafl profusely. May Allah give me and all my friends the strength to earn this blessing.

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(These all articles : Devotion To Salaat,  The Prophet (Sallallaho alaihe wasallam) spends the whole night in Salaat,  The Prophet's (Sallallaho alaihe wasallam) recitation of the Qur'an in Salaat, Salaat of a Few Eminent, Sahabah Salaat of Muhajir and an Ansari keeping watch, Hadhrat Ibn Abbas (Radhi.) and his Salaat, Sahabah's suspending trade at the time of Salaat, Prophet's (Sallallaho Alaihe Wasallam) Company in Paradise courtesy from "Faza'il-E-A'mall By Shaikhul Hadith Maulana Muhammad Zakariya)