What was prepared for those who went.
Gardens already waiting
This completes the verse before. Ibn Kathir says these two verses describe the qualities and the reward of the faithful believers. Those who left the shade of Madinah for the heat find gardens prepared for them, the high grades of Paradise.
You give up the lie-in for Fajr, the weekend for your parents, the extra money for someone in need. It feels like loss at the time. The verse says something has already been prepared in return.
What I give up for Allah is simply gone.
What I give up is answered with something already prepared for me.
Give up one small comfort today for Allah's sake, and tell no one.