Sunan an Nasai
3714
Sahih Lighairihi+2

Hanzalah narrated that he heard Tawus say:"The Messenger of Allah said: 'Ruqba is not permissible. Whoever is given something on the basis of Ruqba, it is part of his estate

Sahih LighairihiAbu Ghuddah
SahihAl-Albani