This is a clear example of what is called ‘consideration of the possibility’.

( وَإِذْ قَالَتْ أُمَّةٌ مِّنْهُمْ لِمَ تَعِظُونَ قَوْمًا ۙ اللَّهُ مُهْلِكُهُمْ أَوْ مُعَذِّبُهُمْ عَذَابًا شَدِيدًا) (And when a community among them said, “Why do you advise [or warn] a people whom Allah is [about] to destroy or to punish with a severe punishment?”): Some of the children of Israel blamed the preachers for preaching the people who were lost in disbelief and disobeyed the commands of Allah (swt), considering this preaching was futile because Allah (swt) will surely destroy them.

( قَالُوا مَعْذِرَةً إِلَىٰ رَبِّكُمْ وَلَعَلَّهُمْ يَتَّقُونَ) (they [the advisors] said, “To be absolved before your Lord and perhaps they may fear Him.”): The advisors gave two reasons for their act of preaching others: The first reason is to offer their excuse before Allah (swt) by explaining and clarifying to Him (swt) that they did in fact clarified the truth and advised them. The second reason is that they had hope that the transgressors might turn away from their wrongdoings, deviation, and disobedience.