What is the ruling regarding praying over the deceased?

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There is great merit in increasing the number of those praying over the deceased, as this yields a reward for the attendees and benefits the deceased. Each person praying accrues a qirat (a measure of reward). The Prophet, peace be upon him, stated that no Muslim dies and three rows of Muslims pray over him except that Paradise becomes incumbent for him. Furthermore, Imam Ahmad narrated from Abu al-Malih that after completing the prayer, he instructed the attendees to straighten their rows and seek good intercession for the deceased. This is supported by a narration from Maymunah, where the Prophet said that when an 'Ummah' (a large group) of people prays over a Muslim, their intercession is accepted for him; Abu al-Malih interpreted 'Ummah' in this context to mean forty people.