I heard the Messenger of Allah ﷺ say, "Tell me, if there were a river flowing by the courtyard of one of you and he bathed in it five times every day, would any dirt remain on him?"They replied, "None at all."He said, "The prayers wash away sins just as water washes away dirt."
حدثنا عبد الله حدثني أبي وأبو خيثمة قالا حدثنا يعقوب قال أبي في حديثه قال أخبرنا ابن أخي ابن شهاب وقال أبو خيثمة حدثني عن عمه قال أخبرني صالح بن عبد الله بن أبي فروة أن عامر بن سعد بن أبي وقاص أخبره أنه سمع أبان بن عثمان يقول
سمعت رسول الله ﷺ يقول أرأيت لو كان بفناء أحدكم نهر يجري يغتسل منه كل يوم خمس مرات ما كان يبقى من درنه قالوا لا شيء قال إن الصلوات تذهب الذنوب كما يذهب الماء الدرن
Its chain of transmission is sahih. Abu Khaythama is Zuhayr bin Harb. Yaqub is Ibn Ibrahim bin Saad. The nephew of Ibn Shihab is Muhammad bin Abdullah bin Muslim bin Ubaydullah bin Abdullah bin Shihab Zuhri. His uncle is the well known Ibn Shihab Zuhri, whose name is Muhammad bin Muslim bin Ubaydullah. Salih bin Abdullah bin Abu Farwa Madani is thiqah. Ibn Main and Ibn Hibban declared him thiqah.This chain actually contains two chains. It was narrated by Abdullah bin Ahmad from his father and from Abu Khaythama, both of them from Yaqub bin Ibrahim from the nephew of Ibn Shihab from his uncle Ibn Shihab Zuhri. Abdullah clarified the exact wording of his two teachers. His father said, Yaqub narrated to us, saying, the nephew of Ibn Shihab narrated to me from his uncle.The hadith was also narrated by Ibn Majah, 1:219, from Abdullah bin Abu Ziyad from Yaqub bin Ibrahim. See also Targheeb wal-Tarheeb, 1:137.