Sayyiduna Ibn Umar (may Allah be pleased with them both) narrates: We were with the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) was eating jummar (the pith of the date palm), and the people were also present, when the Messenger of Allah (peace and blessings be upon him) said: "Among the trees there is a tree that is like the Muslim man." The people remained silent, until I, despite being the youngest of them, was about to ask the Messenger of Allah (peace and blessings be upon him), when he (peace and blessings be upon him) himself said: "It is the date palm."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13464