Muhammad bin 'Ali bin Harb محمد بن علي بن حرب · The Book of Purification

"The Messenger of Allah (ﷺ) said: 'Whoever performs Wudu' and does it well, then says: "Ashhadu an la ilaha ill-Allah was ashhadu anna Muhammadan 'abduhu wa rasuluh (I bear witness that there is none worthy of worship except Allah, and I bear witness that Muhammad is his slave and Messenger)," eight gates of Paradise will be opened for him, and he may enter through whichever one he wishes.'"