If I were to swear by Allah nine times that, indeed, the Messenger of Allah ﷺ has been killed, that would be more beloved to me than swearing only once, because Allah the Exalted took His Prophet and made him into a martyr.  

لَأَنْ أَحْلِفَ بِاللهِ تِسْعًا إِنَّ رَسُولَ اللهِ ﷺ قُتِلَ قَتْلًا أَحَبُّ إِلَيَّ مِنْ أَنْ أَحْلِفَ وَاحِدَةً وَذَلِكَ بِأَنَّ اللهَ ﷻ اتَّخَذَهُ نَبِيًّا وَجَعَلَهُ شَهِيدًا  

If I were to swear by Allah nine times that, indeed, the Messenger of Allah ﷺ has been killed, that would be more beloved to me than swearing only once that he was not killed, because Allah ﷻ took His Prophet and made him into a martyr. He said: Then I mentioned that to Ibrahim, and he said: They used to say that the Jews poisoned him and his Abū Bakr.  

لَأَنْ أَحْلِفَ تِسْعًا أَنَّ رَسُولَ اللهِ ﷺ قُتِلَ قَتْلًا أَحَبُّ إِلَيَّ مِنْ أَنْ أَحْلِفَ وَاحِدَةً أَنَّهُ لَمْ يُقْتَلْ وَذَلِكَ أَنَّ اللهَ ﷻ جَعَلَهُ نَبِيًّا وَاتَّخَذَهُ شَهِيدًا۔ قَالَ: فَذَكَرْتُ ذَلِكَ لِإِبْرَاهِيمَ فَقَالَ كَانُوا يَرَوْنَ وَيَقُولُونَ إِنَّ الْيَهُودَ سَمُّوهُ وَأَبَا بَكْرٍ