Hammad bin Zayd حماد بن زيد بن درهم الأزدي الأزرق · Wills (Kitab Al-Wasaya)

The Messenger of Allah (ﷺ) as saying: When a man dies, his action discontinues from him except three things, namely, perpetual sadaqah (charity), or the knowledge by which benefit is acquired, or a pious child who prays for him.