"Their call therein," meaning: their saying in Paradise, "Exalted are You, O Allah, and their greeting therein is peace," meaning: they greet one another with peace, and the angels greet them on behalf of Allah - Mighty and Majestic is He.
﴿دَعوَاهُم فِيهَا﴾ أَيْ: قَوْلُهُمْ فِي الْجَنَّةِ: ﴿سُبْحَانَكَ اللَّهُمَّ وتحيتهم فِيهَا سَلام﴾ يَعْنِي: يُحَيِّي بَعْضُهُمْ بَعْضًا بِالسَّلامِ، وَتُحَيِّيهِمُ الْمَلائِكَةُ عَنِ اللَّهِ - عَزَّ