Bakr bin Abdullah (may Allah have mercy on him) says that a man came to the Messenger of Allah ﷺ and said: I saw (in a dream) a servant who was writing the Qur'an. When he reached the prostration (sajdah) in Surah Sad, there was a tree nearby which fell down in prostration, and the tree said: "O Allah! For this, write a reward for me, erase my burden, and make it a prostration of gratitude for me." When the Prophet ﷺ heard this dream, he said: "We are more deserving of prostration than the tree." So the Messenger of Allah ﷺ performed prostration and also commanded prostration in this Surah.
Hadith Referenceالسنن المأثورة / باب ما جاء في الصلاة على الراحلة / 94
Hadith Takhrijالسنن الكبرى للبيهقي : 320/2 ، مستدرك حاكم: 432/2 وقال الذهبي على شرط مسلم، مجمع الزوائد للهيثمي : 284/2 وقال رواه احمد ورجاله رجال الصحيح، السلسلة الصحيحة للالباني : 472/6۔