Sunan An-Nasai, Chapter: The Book of Purification

"I heard the Messenger of Allah (saw) offering the (funeral) prayer for one who had died, and I heard him say in his supplication: 'Allahummaghfir lahu warhamhu wa 'afihi wa a'fu 'anhu wa akrim nuzulahu wa wassi' madkhalahu waghsilhu bil-ma'i wath-thalji wal-baradi wa naqqihi min al-khataya kama ynaqqath-thawb al-abyad min ad-danas. (O Allah, forgive him and have mercy on him, keep him safe and sound and forgive him, honor the place where he settles and make his entrance wide; wash him with water and snow and hail, and cleanse him of sin as a white garment is cleansed of dirt)." (Sahih)