When the Prophet ﷺ uttered taslim, he used to say: "O Allah, You are As-Salam, and from you is As-Salam. You are blessed, O One of Magnificence and Generosity."
أَنَّ النَّبِيَّ ﷺ كَانَ إِذَا سَلَّمَ قَالَ اللَّهُمَّ أَنْتَ السَّلاَمُ وَمِنْكَ السَّلاَمُ تَبَارَكْتَ يَا ذَا الْجَلاَلِ وَالإِكْرَامِ