﴿ 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!"”

Please check ayah 12:76 for complete tafsir.