We have found that the deaths of youths is as difficult as the destruction of the Temple. (Eikha Rabba 1;44)
The Ben Ish Hai explains to us that when a young person dies, especially a righteous one, people have questions about Divine justice. “How could this young life be taken away?” If they knew the secrets of reincarnation, they would stop having doubts.
A person who is entering the world for the first time and is righteous will definitely live out their 70 years. But not all of us are here for the first time. When a person dies without fulfilling one’s mission here, G-d forbid, the soul may be sent back again. Then, as soon as the person merits completing their tikkun (soul correction), there mission is complete and they immediately depart.
Like the death of youths, the destruction of the Temple arouses questions about Divine justice. “How could such a holy place be destroyed?” If they truly knew the purpose, they would cease to wonder…
Based on If I Forget Thee, From the Writings of Hacham Yosef Hayyim of Baghdad