Perhaps Peter thought that one of those seats should be for him because Jesus had already said that Peter would have a special role.
(‏ مت ٢٦ :‏ ​ ٣١ -‏ ٣٣‏ )‏ غَيْرَ أَنَّ ثِقَتَهُ بِنَفْسِهِ لَمْ يَكُنْ لَهَا أَيُّ أَسَاسٍ ،‏ ذٰلِكَ أَنَّهُ فِي تِلْكَ ٱللَّيْلَةِ عَيْنِهَا فَشِلَ فِي ٱلْإِعْرَابِ عَنِ ٱلتَّوَاضُعِ .‏