Abu Dawud Book 2, Hadith Number 1444.
Chapter : On standing for a long time in prayer at night.
Narated By ‘Abd Allah b. Habshi al-Khat’ami : The Prophet (PBUH) was asked: Which of the actions is better? He replied: Standing for long time (in prayer). He was again asked: Which alms is better? He replied: The alms given by a man possessing small property acquired by his labour.