Surah An-Naml, Verse 49

قَالُواْ تَقَاسَمُواْ بِٱللَّهِ لَنُبَيِّتَنَّهُۥ وَأَهۡلَهُۥ ثُمَّ لَنَقُولَنَّ لِوَلِيِّهِۦ مَا شَهِدۡنَا مَهۡلِكَ أَهۡلِهِۦ وَإِنَّا لَصَٰدِقُونَ٤٩

qālū taqāsamū bil-lahi lanubayyitannahu wa-ahlahu thumma lanaqūlanna liwaliyyihi mā shahid'nā mahlika ahlihi wa-innā laṣādiqūna

They said, "Take a mutual oath by Allāh that we will kill him by night, he and his family. Then we will say to his executor, 'We did not witness the destruction of his family, and indeed, we are truthful.'"