This is the essence of all sciences

You know the value of every article of merchandise,
but if you don't know the value of your own soul,
it's all foolishness.
You've come to know the fortunate and the inauspicious stars,
but you don't know whether you yourself
are fortunate or unlucky.
This, this is the essence of all sciences-
that you should know who you will be
when the Day of Reckoning arrives.

Mathnawi III, Maulana Jallaluddin Rumi, may Allah sanctify his soul & bless his secret