Their mourning is sadness over their own sinful state and the conditions existing because of human imperfection. Why are such mourners “happy ”?
لِأَنَّهُمْ يُمَارِسُونَ ٱلْإِيمَانَ بِٱللهِ وَٱلْمَسِيحِ ،‏ وَيَنَالُونَ ٱلتَّعْزِيَةَ مِنْ عَلَاقَتِهِمِ ٱلْجَيِّدَةِ بِيَهْوَه .‏ —‏ يو ٣ :‏ ٣٦‏ .‏