Sahih al-Bukhari 61
Narrated Ibn `Umar:
Allah's Messenger (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 but felt shy to answer the others then asked, "What is that tree, O 
Allah's Messenger (ﷺ) ?" He replied, "It is the date-palm tree."
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ جَعْفَرٍ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنِ ابْنِ عُمَرَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ إِنَّ مِنَ الشَّجَرِ شَجَرَةً لاَ يَسْقُطُ وَرَقُهَا، وَإِنَّهَا مَثَلُ الْمُسْلِمِ، فَحَدِّثُونِي مَا هِيَ ‏"‏‏.‏ فَوَقَعَ النَّاسُ فِي شَجَرِ الْبَوَادِي‏.‏ قَالَ عَبْدُ اللَّهِ وَوَقَعَ فِي نَفْسِي أَنَّهَا النَّخْلَةُ، فَاسْتَحْيَيْتُ ثُمَّ قَالُوا حَدِّثْنَا مَا هِيَ يَا رَسُولَ اللَّهِ قَالَ ‏"‏ هِيَ النَّخْلَةُ ‏"‏‏.‏