al-Fadl bin al-Sbah al-Bghdady الفضل بن الصباح البغدادي · Chapters on Knowledge

from his father that the Messenger of Allah (ﷺ) said: "Whoever starts a good tradition which is followed, then for him is a reward, and the likes of their rewards of whoever follows him, there being nothing diminished from their rewards. And whoever starts a bad tradition which is followed, then for him is the sin, and the likes of the sins of whoever follows him, there being nothing diminished from their sins."