Is the saying “If you knew the unseen you would be content with what happened to you” correct?

This saying
is not a hadeeth from the Prophet (blessings and peace of Allah be upon him)
and it is not narrated from any of his Companions; rather we do not know of
anyone who is an authority in Islamic knowledge who said it or approved of
its meaning. 

Moreover,
this saying is not correct in and of itself; rather it is false and is
contrary to what Allah has instilled in His slaves of keenness to seek good
and ward off harm. If it so happens that a person travels and an accident
befalls him or his family or his wealth, it would not be said that if he had
known the unseen before he travelled and that an accident would befall him,
that with that prior knowledge he would still have travelled. No one would
say such a thing and no wise person would do that at all. 

Rather the
meaning that is intended by this phrase is that the alternative to this
accident that befell him would have been more harmful and worse. If he had
not travelled, then he would have died, for example, or he would have met
with an accident that was worse than the one that did befall him. Because of
that people say: you would have been content with what befell you because it
was the lesser of two evils and the smaller of two losses. 

Undoubtedly
this is speculation based on false assumptions and speaking of Allah without
knowledge. The notion that being saved from this calamity would inevitably
mean that something worse would happen to him is in fact more akin to
thinking negatively of Allah and His decree. 

One of the
things that indicate that this saying is false is the verse in which Allah,
may He be exalted, says:

“Say (O
Muhammad SAW): I possess no power of benefit or hurt to myself except as
Allah wills. If I had the knowledge of the Ghaib (unseen), I should have
secured for myself an abundance of wealth, and no evil should have touched
me. I am but a warner, and a bringer of glad tidings unto people who
believe.”

[al-A‘raaf
7:188]. 

Abu Hayyaan
(may Allah have mercy on him) said: 

That is, my
situation would have been different and I would have secured for myself an
abundance of wealth and avoided evil and harm so that none of that would
have touched me.

End quote
from al-Bahr al-Muheet, 4/355 

As-Sa‘di
(may Allah have mercy on him) said:

That is, I
would have done the things that I know would have served my interests and
brought me benefits, and I would have avoided anything that could have led
to bad outcomes and negative consequences, because I would have known about
things before they happened and what their outcomes would have been. 

But I –
because of my lack of knowledge – have been affected by bad things and I
have missed out on worldly interests and benefits; this is the clearest
indication that I have no knowledge of the unseen.

End quote
from Tafseer as-Sa‘di, 311 

Ibn ‘Ashoor
(may Allah have mercy on him) said: 

The
statement that he has no power to bring benefit for himself or ward off harm
comes before the statement that he has no knowledge of the unseen, because
the aim behind people’s desire to know the unseen is to try to hasten the
future good by taking measures to guarantee it and bring it closer, and to
avoid harm. So stating that he has no power to bring benefit for himself or
ward off harm includes all kinds of power and all kinds of benefits and
harm, and that includes whatever of that there may be in the future, which
is part of the unseen.

End quote
from at-Tahreer wa’t-Tanweer, 9/207-208 

From all of
the above it becomes clear that a person may miss out on some good or be
affected by some bad and harm because of his ignorance of that which is
hidden from him (the unseen), and that if he were to know of these unseen
matters, he could have taken measures to protect himself from what already
befell him of harm and he could have taken measures to attain what he
already missed of good.  

And Allah knows best.