They can fill us in on events that are mentioned in the Bible but not described in detail.
وَسَوْفَ يُخْبِرُونَنَا بِتَفَاصِيلِ أَحْدَاثٍ أَتَى ٱلْكِتَابُ ٱلْمُقَدَّسُ عَلَى ذِكْرِهَا وَلكِنَّهُ لَمْ يَتَوَسَّعْ فِيهَا .‏