Problems that make a person physically strong.
A BIOLOGY teacher taught his students how a butterfly comes out of the mold and into a butterfly. He told his students that when a butterfly tries to get out of the mold, no one should help it out. He said this and left the classroom.
The disciples were waiting. The butterfly was trying to get out. A student helped out of pity and broke the mold. The butterfly came out but died a few minutes later. When the master returned, he inquired about the cause of death. He said that the butterfly tries to get out and suffers, this suffering is like a sport that strengthens its wings and feeds and prepares it for life in this world. This student did not allow him to strengthen himself with his efforts, he remained weak and could not survive.
Imam Ali (AS) in his famous letter to Uthman bin Hanif says:
(1); Be aware that desert trees have harder wood and trees along the creek have thinner bark. Desert-irrigated desert trees are more flammable and more durable. Imam's intention is that because desert trees grow and develop in extreme hardness, they are harder than other trees.
Only if we face resistance, we can grow strong.