The Messenger of Allah ﷺ forbade najsh.
أن رسول الله ﷺ نهي عن النجش.
No references are available.
Malik narrated it in "Sales" (97) from Nafi from Abdullah bin Umar, and he related it. Bukhari narrated it in "Sales" (2142), and Muslim in "Sales" (1516), both through the route of Malik, with the same wording.