SHAFAQNA – Sheikh Sadooq according to authentic documents, narrated from Imam Sadeq (AS) that one of Imam’s close companions came to see Imam (AS) towards the end of the month of Rajab. Imam Sadeq (AS) asked: Have you fasted this month? He replied: No, Imam (AS) said: You lost so much rewards which only God knows the measure of them; this is a month which Allah (SWT) has given it a great respect and lots of rewards are given for fasting in this month.
He asked: If I fast in the remaining days of this month, will I be rewarded for them? Imam Sadeq (AS) replied: Yes; then Imam (AS) described the rewards for fasting the last day, the last two days and the last three days of the month of Rajab; like being saved from difficulties of death, being saved from torments of the grave, difficulties on the Day of Judgment and the hellfire . In another narration it is said: Rajab is the name of a river in paradise, it is whiter than milk and sweeter than honey; any one who fasts a day in this holy month, will drink from this river .
 Amaali, Sheikh Sadooq, Q 15.
 Iqbaal, Page 635.