Sahih al-Bukhari 62Book 3, Hadith 4
حَدَّثَنَا خَالِدُ بْنُ مَخْلَدٍ، حَدَّثَنَا سُلَيْمَانُ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ دِينَارٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " إِنَّ مِنَ الشَّجَرِ شَجَرَةً لاَ يَسْقُطُ وَرَقُهَا، وَإِنَّهَا مَثَلُ الْمُسْلِمِ، حَدِّثُونِي مَا هِيَ ". قَالَ فَوَقَعَ النَّاسُ فِي شَجَرِ الْبَوَادِي. قَالَ عَبْدُ اللَّهِ فَوَقَعَ فِي نَفْسِي أَنَّهَا النَّخْلَةُ، ثُمَّ قَالُوا حَدِّثْنَا مَا هِيَ يَا رَسُولَ اللَّهِ قَالَ " هِيَ النَّخْلَةُ ".
The Prophet (ﷺ) said, "Amongst the trees, there is a tree, the leaves of which do not fall and is like a Muslim. Tell me the name of that tree." Everybody started thinking about the trees of the desert areas. And I thought of the date-palm tree. The others then asked, "Please inform us what is that tree, O Allah's Messenger (ﷺ)?" He replied, "It is the date-palm tree."