"And when it is said to them, 'Do not cause corruption on the earth,'" meaning: Do not commit shirk (polytheism). "They say, 'We are but reformers,'" meaning: They manifested faith.
﴿وَإِذَا قِيلَ لَهُمْ لَا تُفْسِدُوا فِي الأَرْض﴾ يَعْنِي: لَا تُشْرِكُوا ﴿قَالُوا إِنَّمَا نَحن مصلحون﴾ أَي: أظهرُوا الْإِيمَان
