I and Messenger of Allah ﷺ happened to pass by people near the date-palm trees. He (the Holy Prophet) said: What are these people doing? They said: They are grafting, i. e. they combine the male with the female (tree) and thus they yield more fruit. Thereupon Messenger of Allah ﷺ said: I do not find it to be of any use. The people were informed about it and they abandoned this practice. Messenger of Allah ﷺ (was later) on informed (that the yield had dwindled), whereupon he said: If there is any use of it, then they should do it, for it was just a personal opinion of mine, and do not go after my personal opinion; but when I say to you anything on behalf of Allah, then do accept it, for I do not attribute lie to Allah, the Exalted and Glorious.  

مَرَرْتُ مَعَ رَسُولِ اللَّهِ ﷺ بِقَوْمٍ عَلَى رُءُوسِ النَّخْلِ فَقَالَ مَا يَصْنَعُ هَؤُلاَءِ فَقَالُوا يُلَقِّحُونَهُ يَجْعَلُونَ الذَّكَرَ فِي الأُنْثَى فَيَلْقَحُ فَقَالَ رَسُولُ اللَّهِ ﷺ مَا أَظُنُّ يُغْنِي ذَلِكَ شَيْئًا قَالَ فَأُخْبِرُوا بِذَلِكَ فَتَرَكُوهُ فَأُخْبِرَ رَسُولُ اللَّهِ ﷺ بِذَلِكَ فَقَالَ إِنْ كَانَ يَنْفَعُهُمْ ذَلِكَ فَلْيَصْنَعُوهُ فَإِنِّي إِنَّمَا ظَنَنْتُ ظَنًّا فَلاَ تُؤَاخِذُونِي بِالظَّنِّ وَلَكِنْ إِذَا حَدَّثْتُكُمْ عَنِ اللَّهِ شَيْئًا فَخُذُوا بِهِ فَإِنِّي لَنْ أَكْذِبَ عَلَى اللَّهِ ﷻ  

The Messenger of Allah ﷺ passed by some people who were at the top of the palm trees. He said: ʿWhat are these people doing?ʿ They said: “They are pollinating (the trees), putting the male with the female.” He said: ʿI do not think this can help in any way.” They were told about that and they stopped doing it. News of that reached the Messenger of Allah ﷺ and he said: “If it will benefit them, then let them do it. It was only a passing thought. Do not blame me for a mere thought, but if I tell you anything about Allah (may He be glorified and exalted) then accept it from me, for I will never tell a lie about Allah.ʿ  

مَرَّ رَسُولُ اللهِ ﷺ عَلَى قَوْمٍ فِي رُءُوسِ النَّخْلِفَقَالَ مَا يَصْنَعُ هَؤُلاءِ؟ قَالُوا يُلَقِّحُونَهُ يَجْعَلُونَ الذَّكَرَ فِي الْأُنْثَى قَالَ مَا أَظُنُّ ذَلِكَ يُغْنِي شَيْئًا فَأُخْبِرُوا بِذَلِكَ فَتَرَكُوهُ فَأُخْبِرَ رَسُولُ اللهِ ﷺ فَقَالَ إِنْ كَانَ يَنْفَعُهُمْ فَلْيَصْنَعُوهُ فَإِنِّي إِنَّمَا ظَنَنْتُ ظَنًّا فَلا تُؤَاخِذُونِي بِالظَّنِّ وَلَكِنِ إذَا أَخْبَرْتُكُمْ عَنِ اللهِ ﷻ بِشَيْءٍ فَخُذُوهُ فَإِنِّي لَنِ أكْذِبَ عَلَى اللهِ شَيْئًا