ENOfficial
Abu Musa al-Ash‘ari reported God’s messenger as saying, "He who plays backgammon has disobeyed God and His messenger." Ahmad and Abu Dawud transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ أَبِي مُوسَى الْأَشْعَرِيِّ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «مَنْ لَعِبَ بِالنَّرْدِ فَقَدْ عَصَى اللَّهَ وَرَسُولَهُ» . رَوَاهُ أَحْمَدُ وَأَبُو دَاوُد
sunnah.com