Abdullah bin Umar reported,

The Messenger of Allah ﷺ said, "Among the trees there is one whose leaves do not fall, and it is like the Muslim. Tell me, which tree is it?"The people began guessing trees of the desert.Abdullah bin Umar said, "It occurred to me that it was the date palm, but I felt too shy to speak."Then they said, "Tell us what it is, Messenger of Allah."He said, "It is the date palm."In another narration, "Tell me of a tree that is like the Muslim, which yields its fruit at every season by the permission of its Lord, and whose leaves do not fall." It occurred to me that it was the date palm, but I disliked speaking up while Abu Bakr and Umar were present. When neither of them spoke, the Prophet ﷺ said, "It is the date palm."When I went out with my father, I said, "Father, it had occurred to me that it was the date palm."He said, "What kept you from saying it? Had you said it, that would have been dearer to me than such and such."I said, "Nothing kept me from it except that I did not see you or Abu Bakr speak, so I disliked to speak."

عن ابن عمر قال

قال رسول الله ﷺ: إن من الشجر شجرة لا يسقط ورقها، وإنها مثل المسلم، فحدثوني ما هي؟ فوقع الناس في شجر البوادي. قال عبد الله بن عمر: ووقع في نفسي أنها النخلة فاستحييت، ثم قالوا: حدثنا ما هي يا رسول الله، قال: هي النخلة. وفي رواية: أخبروني شجرة مثلها مثل المسلم، تؤتي أكلها كل حين بإذن ربها، ولا تحت ورقها فوقع في نفسي: النخلة، فكرهت أن أتكلم وثم أبو بكر وعمر، فلما لم يتكلما قال النبي ﷺ: هي النخلة. فلما خرجت مع أبي قلت: يا أبتاه، وقع في نفسي النخلة. قال: ما منعك أن تقولها؟ لو كنت قلتها كان أحب إلي من كذا وكذا. قال: ما منعني إلا أني لم أرك ولا أبا بكر تكلمتما فكرهت.