1)
What do we learn from "Ki Lo l'Olam Chosen v'Im Nezer l'Dor va'Dor"?
1.
Rashi: If you are rich with silver and gold, perhaps it will not last forever. Therefore, do not belittle your small matters.
2.
Malbim: Even if you have great wealth, do not rely on it; it is not forever. Perhaps you will wax poor. Also if you have a crown 1 that will last your entire life, it is not for all generations. Perhaps your children will not inherit it!
1
A position of authority (PF). When Mar Zutra Chasida taught in the gathering before the festival, and they carried him on their shoulders, he would say our verse (Yuma 87a).