Hadith ~ Which sadaqa has the greatest reward

Abu Hurayra said, "A man came to the Prophet, may Allah bless him and grant him peace, and said, 'O Messenger of Allah, which sadaqa has the greatest reward?' He said, 'The sadaqa that you give when you are healthy but tight-fisted, in fear of poverty and desiring wealth. Do not put it off until death is near and you say, "So-and-so should have this much and so-and-so this much,"' when it already belongs to someone else." [Agreed upon]

Riyad as-Salihin (The Meadows of the Righteous) of Iman Mohieddine Annawawi 631-676.  Chapter 10: "On hastening to perform good actions, and on encouraging the one who intends to do something to go ahead and do it with diligence and not to hesitate", Hadith Number: 90.