The Best prayer is Dua’a
The Holy Prophet (PBUH) of God has been quoted as saying: “The best prayer is Dua’a. When God inspires someone with Dua’a, He opens the door of Mercy to him. A man of Dua’a will never become wretched.”
Source: imamreza.net
Other links:
An Ornament of the Hereafter
Three Characteristics of a Believer
The Most Pious of the People
True Muslim
