"A man said to Ibn Mas'ud: 'Which deed is most virtuous?' He said: 'I asked Allah's Messenger (that). He said: "Salat at the beginning of its time." I asked him: "What is after that O Messenger of Allah?" He said: "Being dutiful to one's parents." I said: "What is after that ?" He said: "Jihad in the Way of Allah."
Jami` at-Tirmidhi Book 2, Hadith 25