Talhah reported: I passed by some people with the Messenger of Allah, peace and blessings be upon him, who were on top of palm trees. The Prophet said, “What are you doing?” They said, “They are grafting them, mixing the male and female to produce more yield.” The Prophet said, “I do not expect it will amount to anything.” They were informed about that and abandoned the practice, but the yield was lower. The Prophet was told about it later and he said, “If that is beneficial, let them do it. Verily, I only had an opinion, so do not take my opinion. Rather, if I narrate to you anything from Allah, then take it. I do not lie against Allah Almighty.”
Source: Ṣaḥīḥ Muslim 2361
Grade: Sahih (authentic) according to Muslim
عَنْ طَلْحَةَ قَالَ مَرَرْتُ مَعَ رَسُولِ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ بِقَوْمٍ عَلَى رُءُوسِ النَّخْلِ فَقَالَ مَا يَصْنَعُ هَؤُلَاءِ فَقَالُوا يُلَقِّحُونَهُ يَجْعَلُونَ الذَّكَرَ فِي الْأُنْثَى فَيَلْقَحُ فَقَالَ رَسُولُ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ مَا أَظُنُّ يُغْنِي ذَلِكَ شَيْئًا قَالَ فَأُخْبِرُوا بِذَلِكَ فَتَرَكُوهُ فَأُخْبِرَ رَسُولُ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ بِذَلِكَ فَقَالَ إِنْ كَانَ يَنْفَعُهُمْ ذَلِكَ فَلْيَصْنَعُوهُ فَإِنِّي إِنَّمَا ظَنَنْتُ ظَنًّا فَلَا تُؤَاخِذُونِي بِالظَّنِّ وَلَكِنْ إِذَا حَدَّثْتُكُمْ عَنِ اللهِ شَيْئًا فَخُذُوا بِهِ فَإِنِّي لَنْ أَكْذِبَ عَلَى اللهِ عَزَّ وَجَلَّ
2361 صحيح مسلم كتاب الفضائل باب وجوب امتثال ما قاله شرعا دون ما ذكره صلى الله عليه وسلم من معايش الدنيا على سبيل الرأي