On the authority of some men of the Ansar : The Prophet ﷺ said to the Jews and started with them: Fifty of you should take the oaths. But they refused (to take the oaths). He then said to the Ansar: Prove your claim. They said: Do we take the oaths without seeing, Messenger of Allah? The Messenger of Allah ﷺ then imposed the blood-wit on the Jews because he (the slain) was found among them.
أَنَّ النَّبِيَّ ﷺ قَالَ لِلْيَهُودِ وَبَدَأَ بِهِمْ يَحْلِفُ مِنْكُمْ خَمْسُونَ رَجُلاً فَأَبَوْا فَقَالَ لِلأَنْصَارِ اسْتَحِقُّوا قَالُوا نَحْلِفُ عَلَى الْغَيْبِ يَا رَسُولَ اللَّهِ فَجَعَلَهَا رَسُولُ اللَّهِ ﷺ دِيَةً عَلَى يَهُودَ لأَنَّهُ وُجِدَ بَيْنَ أَظْهُرِهِمْ