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. (Using translation from Aḥmad 4139)  

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

[Machine] That the Messenger of Allah ﷺ was killed is more beloved to me than taking a single oath, because he was not killed. That is because Allah, the Almighty and Glorious, made him a prophet and made him a witness.  

أَنَّ رَسُولَ اللَّهِ ﷺ قُتِلَ قَتْلًا أَحَبُّ إِلَيَّ مِنْ أَنْ أَحْلِفَ وَاحِدَةً إِنَّهُ لَمْ يُقْتَلْ وَذَلِكَ أَنَّ اللَّهَ ﷻ اتَّخَذَهُ نَبِيًّا وَاتَّخَذَهُ شَهِيدًا»  

[Machine] "I swear by nine that the Ibn Sayyad is the Dajjal is more beloved to me than swearing by one, and I swear by nine that the Messenger of Allah ﷺ was martyred is more beloved to me than swearing by one that he was not martyred because Allah made him a prophet and took him as a martyr."  

«لَأَنْ أَحْلِفَ تِسْعًا أَنَّ ابْنَ صَيَّادٍ هُوَ الدَّجَّالُ أَحَبُّ إِلَيَّ مِنْ أَحْلِفَ وَاحِدَةً وَلَأَنْ أَحْلِفَ تِسْعَةً أَنَّ رَسُولَ اللهِ ﷺ قُتِلَ شَهِيدًا أَحَبُّ إِلَيَّ مِنْ أَنْ أَحْلِفَ وَاحِدَةً أَنَّهُ لَمْ يُقْتَلْ ذَلِكَ أَنَّ اللهَ ﷻ جَعَلَهُ نَبِيًّا وَاتَّخَذَهُ شَهِيدًا»