The Dearest Deed To Allah. 

Narrated by ‘Abdullah:

    I asked the Prophet “Which deed is the dearest to Allah?” He replied, “To offer the prayers at their early stated fixed times.” I asked, “What is the next (in goodness)?” He replied, “To be good and dutiful to your parents” I again asked, “What is the next (in goodness)?” He replied, ‘To participate in Jihad (religious fighting) in Allah’s cause.” ‘Abdullah added, “I asked only that much and if I had asked more, the Prophet would have told me more.”

[bukhari Vol 1 Book 10 Hadith 505]