Sunan Ibn Majah
2137
Sahih+2

It was narrated from 'Aishah that the Messenger of Allah (ﷺ) said:'The best (most pure) food a man consumes is that which he has earned himself, and his child (and his child's wealth) is part of his earnings

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi