Sayyiduna Abdullah bin Hubshi (may Allah be pleased with him) says that the Prophet (peace and blessings be upon him) was asked: Which deeds are best? He (peace and blessings be upon him) said: "Faith in which there is no doubt, jihad in which there is no treachery, and an accepted Hajj." Then he was asked: Which prayer is most virtuous? He (peace and blessings be upon him) said: "The one with long standing."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4690