Surah An-Naml 27:49

قَالُوا۟ تَقَاسَمُوا۟ بِٱللَّهِ لَنُبَيِّتَنَّهُۥ وَأَهْلَهُۥ ثُمَّ لَنَقُولَنَّ لِوَلِيِّهِۦ مَا شَهِدْنَا مَهْلِكَ أَهْلِهِۦ وَإِنَّا لَصَـٰدِقُونَ

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.'"

Translation: Saheeh International

Tafsir

They said that is some said to others ‘Swear to one another by God that we will attack him by night la-nubayyitannahu; or read la-tubayyitunnahu ‘that you will attack him by night’ together with his folk that is those who believed in him in other words swear that we will kill them at night; …

Excerpt from Tafsir al-Jalalayn, commentary on 27:49, via Quran.com. The reader has the full commentary and 9 more tafsirs.