Sunan Ibn Majah, Volume 5, Book 33, Hadith 3807 (DarusSalam) ⓘ

It was narrated from Abu Hurairah that : the Messenger of Allah passed by him when he was planting a plant, and said: "O Abu Hurairah, what are you planting?" I said: "A plant for me." He said: "Shall I not tell you of a plant that is better than this?" He said: "Of course, O Messenger of Allah." He said: "Say: 'Subhan-Allah, wal-hamdu-lillah, wa la ilaha illallah, wa Allahu Akbar (Glory is to Allah, praise is to Allah, none has the right to be worshiped but Allah and Allah is the Most Great.)' For each one a tree will be planted for you in Paradise."

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَفَّانُ، حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ أَبِي سِنَانٍ، عَنْ عُثْمَانَ بْنِ أَبِي سَوْدَةَ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ مَرَّ بِهِ وَهُوَ يَغْرِسُ غَرْسًا فَقَالَ ‏"‏ يَا أَبَا هُرَيْرَةَ مَا الَّذِي تَغْرِسُ ‏"‏ ‏.‏ قُلْتُ غِرَاسًا لِي ‏.‏ قَالَ ‏"‏ أَلاَ أَدُلُّكَ عَلَى غِرَاسٍ خَيْرٍ لَكَ مِنْ هَذَا ‏"‏ ‏.‏ قَالَ بَلَى يَا رَسُولَ اللَّهِ ‏.‏ قَالَ ‏"‏ قُلْ سُبْحَانَ اللَّهِ وَالْحَمْدُ لِلَّهِ وَلاَ إِلَهَ إِلاَّ اللَّهُ وَاللَّهُ أَكْبَرُ يُغْرَسْ لَكَ بِكُلِّ وَاحِدَةٍ شَجَرَةٌ فِي الْجَنَّةِ ‏"‏ ‏.‏