Miguel De Unamuno said this quote

Life is doubt,And faith without doubt is nothing but death.

~ Miguel De Unamuno

Only he who attempts the absurd is capable of achieving the impossible.

~ Miguel De Unamuno

Those who believe that they believe in God, but without passion in their hearts, without anguish in mind, without uncertainty, without doubt, without an element of despair even in their consolation, believe only in the God idea, not God Himself.

~ Miguel De Unamuno

Faith which does not doubt is dead faith. -Miguel de Unamuno, philosopher and writer (1864-1936)

~ Miguel De Unamuno