وَلَا نَأْمَنُ عَلَيْهِمْ وَلَا نَشْهَدُ لَهُمْ بِالْجَنَّةِ
We do not regard them as beyond all concern, nor do we testify with certainty that particular persons are in Paradise.
Outward righteousness deserves respect, but Allah knows each person's ultimate end. Without an explicit revealed assurance, a person's private assessment cannot guarantee Paradise to a named believer.
Hope for mercy is accompanied by humility and concern for one's final state.