Surah Al Ahzab Tafseer

تَحِيَّتُهُمْ يَوْمَ يَلْقَوْنَهُ سَلَمٌ

Their greeting on the Day they shall meet Him will be "Salam!"

The apparent meaning -- and Allah knows best -- is that their greeting, from Allah on the Day that they meet Him, will be Salam, i.e., He will greet them with Salam, as He says elsewhere:

سَلَمٌ قَوْلاً مِّن رَّبٍّ رَّحِيمٍ

(It will be said to them):Salam -- a Word from the Lord, Most Merciful. (36:58)

Qatadah claimed that the meaning was that they would greet one another with Salam on the Day when they meet Allah in the Hereafter.

This is like the Ayah:

دَعْوَهُمْ فِيهَا سُبْحَـنَكَ اللَّهُمَّ وَتَحِيَّتُهُمْ فِيهَا سَلَمٌ وَءَاخِرُ دَعْوَاهُمْ أَنِ الْحَمْدُ للَّهِ رَبِّ الْعَـلَمِينَ

Their way of request therein will be `Glory to You, O Allah,' and `Salam' will be their greetings therein! and the close of their request will be `All praise is due to Allah, the Lord of all that exits.' (10:10)

وَأَعَدَّ لَهُمْ أَجْرًا كَرِيمًا

And He has prepared for them a generous reward.

means Paradise and everything in it of food, drink, clothing, dwellings, physical pleasure, luxuries and delightful scenes, such as no eye has seen, no ear has heard and has never entered the mind of man