Holy Prophet (s.a.w.a.) says that on the night of Meeraj, Janabe
Jibrael took me by the permission of Allah to see the castles in
paradise. I saw that the castles were made up of gold and
silver. They were adorned with Musk and Amber. I noticed
some of the castles were glowing and beautiful as compared to
others. I asked Janabe Jibrael why some of these palaces were
not as beautiful and decorated as compared to the others.
Janabe Jibrael informed me that these castles belonged to those
people who were lazy while reciting salawaat on you and your
progeny after namaaz. If they overcome their indolence while
reciting salawaat after namaaz their palaces will also be
adorned otherwise they will remain like this. When the
inhabitants of the paradise will watch these palaces, they will
be informed that the owners of these palaces were lethargic
while reciting salawaat on Mohammad (s.a.w.a.) and his
progeny after namaaz.
Ref : Fazila e Salawaat