Be not deceived with the first appearance of things, for show is not substance.
— English Proverbs

The meeting of two personalities is like the contact of two chemical substances: if there is any reaction, both are transformed.
Carl Jung substance quote

Suffering is the substance of life and the root of personality, for it is only suffering that makes us persons.
— Miguel de Unamuno

Beware lest you lose the substance by grasping at the shadow.
— Aesop

My fear... is my substance, and probably the best part of me.
— substance quotation by Franz Kafka