Surah An-Nisa' (The Women), Verse 2

وَاٰتُوا الْیَتٰمٰۤی اَمْوَالَهُمْ وَلَا تَتَبَدَّلُوا الْخَبِیْثَ بِالطَّیِّبِ وَلَا تَاْكُلُوْۤا اَمْوَالَهُمْ اِلٰۤی اَمْوَالِكُمْ اِنَّهٗ كَانَ حُوْبًا كَبِیْرًا ۟

Wa aatul yataamaaa amwaalahum wa laa tatabad dalul khabeesa bittaiyibi wa laa ta'kulooo amwaalahum ilaaa amwaalikum; innahoo kaana hooban kabeeraa

“To orphans restore their property (When they reach their age), nor substitute (your) worthless things for (their) good ones; and devour not their substance (by mixing it up) with your own. For this is indeed a great sin.”

Quran 4:2 (Yusuf Ali Translation)