Tomorrow marks a day of great humiliation for Satan and whoever fasts will be forgiven for two years of sins, the Friday sermon says.
The sermon says the day of Arafat, the day before Eid Al Adha, when pilgrims climb Mt Arafat, is a day of purification and blessings.
It cites a hadith by the Prophet Mohammed that says there is no day where people are set free from hellfire more than the day of Arafat, when Allah shows off his worshippers in front of the angels.
"It is the day of forgiveness; pilgrims stand on Arafat, where blessings descend … and they return purified of sins, similar to the day their mothers gave birth to them," the sermon says.
Another hadith by the Prophet Mohammed says the devil is at his lowest on the day of Arafat because of what he saw of the blessings and forgiveness from God of the greatest of sins.
It is also traditional for Muslims who are not performing Haj to fast on that day, as the Prophet Mohammed once said it erased the sins of the previous and remaining year.
"It is amazing - you feel it is Judgment Day because you find all the people busy racing time," said Rula Mohammed, 32, a family counsellor from the Palestinian Territories, describing her experience on Mt Arafat when she performed Haj a few years ago.
"I did not want time to pass. The day counts from noon until sunset. You feel it is a race, and who will win to be released from hellfire."
Even though Ramadan has similar benefits, especially on the night of empowerment, the exact date of which is unknown, Arafat is special in its own sense.
"Laylat El Qader is mysterious but Arafat is known, so you feel there is more responsibility to seize the day's benefits," Ms Mohammed said.
"And once it hits maghrib you have to wait a whole year before it comes back."