Sahih al-Bukhari 6962
Sahih al-Bukhari · Book 90: Tricks · What tricks are disliked in bargains
Narrated Abu Huraira:
حَدَّثَنَا إِسْمَاعِيلُ ، حَدَّثَنَا مَالِكٌ ، عَنْ أَبِي الزِّنَادِ ، عَنِ الأَعْرَجِ ، عَنْ أَبِي هُرَيْرَةَ ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " لاَ يُمْنَعُ فَضْلُ الْمَاءِ لِيُمْنَعَ بِهِ فَضْلُ الْكَلإِ " .
Allah's Messenger (ﷺ) said, "One should not prevent others from watering their animals with the surplus of his water in order to prevent them from benefiting by the surplus of grass."