It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that he said: I asked the Messenger of Allah (peace and blessings be upon him): Which deeds are best? He (peace and blessings be upon him) said: "Offering the prayer at the beginning of its time." I said: Then which? He (peace and blessings be upon him) said: "Striving (jihad) in the path of Allah." I said: Then which? He (peace and blessings be upon him) said: "Being dutiful to parents."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2043