﴿ قَالُوا۟ تَٱللَّهِ لَقَدْ عَلِمْتُم مَّا جِئْنَا لِنُفْسِدَ فِى ٱلْأَرْضِ وَمَا كُنَّا سَٰرِقِينَ ﴾

“Said [the brothers]: "By God! Well do you know that we have not come to commit deeds of corruption in this land, and that we have not been thieving!"”

They said ‘By God’ ta’Llāhi is an oath entailing astonishment ‘You know very well that we did not come to work corruption in the land and we are certainly not thieves’ that is we have never stolen anything.