' The soul and mind '...

The soul brings its light from Heaven; the mind acquires its
knowledge from earth. Therefore, when the soul believes readily, the
mind may still doubt.

Bowl of Saki, by Hazrat Inayat Khan

Commentary by Pir-o-Murshid Inayat Khan:

Belief is natural, and disbelief is unnatural, for belief is born in
man, and unbelief is acquired. ... Every child born on earth is born
with a tendency to believe what is told him, but the experience of
the individual in this world full of falsehood teaches man to
disbelieve. That shows that every soul comes from the world of truth,
and opens his eyes in the world of falsehood. Every child comes into
the world with that purity of heart whose natural tendency is to
believe and later he acquires the tendency to doubt. The Prophet has
therefore said: 'Every child is born a believer, it is afterwards
that he becomes an unbeliever.' ... For doubt is earth-born and
belief is heaven-born.

The tendency to doubt, to be depressed, the tendency towards fear,
suspicion and confusion, the tendency to puzzle -- where does it all
come from? It all comes from the thought of getting something in
return: 'will another give me back what I have given him? Shall I get
the just portion back, or less?' if that is the thought behind one's
acts there will be fear, doubt, suspicion, puzzle and confusion. For
what is doubt? Doubt is a cloud that stands before the sun, keeping
it from shining its light. So is doubt: gathering around the soul it
keeps its light from shining out, and man becomes confused and
perplexed. Once selflessness is developed, it breaks through the
cloud saying, 'What do I care whether anyone appreciates it; I only
know to give my service, and that is all my satisfaction. I do not
look forward to get it back. I have given and it is finished; this is
where my duty ends.' That person is blessed, because he has
conquered, he has won.

Understanding does not depend upon the head; it depends upon the
heart. By the help of the head one can make it more clear, it becomes
intelligible and one can express it better. But to begin with it must
come from the heart, not from the head. Besides, a person who only
uses his head says, 'It must be so because I think it is so', whereas
the person who has the heart quality says, 'It is so because I
believe it to be so'. That is the difference. In one person there is
a doubt, in the other there is conviction. ... Spiritual attainment
is nothing but conviction. ... When a person arrives at the stage
when the knowledge of reality becomes a conviction, then there is
nothing in the world that will change it. And if there is anything to
attain to, it is that conviction which one can never find in the
outside world; it must rise from the depths of one's own heart.