The word of God tells us that as we believe so we shall receive!
Mark 11:24
Matthew 9:29
Matthew 8;13
Mark 11:23
Excerpt from Think & Grow Rich
(https://archive.org/details/Think_and_Grow_Rich)
"It is a well known fact that one comes, finally, to BELIEVE whatever one repeats to one’s self, whether the statement be true or false [...]
The psychologists have named this law “auto-suggestion,” and let it go at that. The name by which one calls this law is of little importance. The important fact about it is-it WORKS for the glory and success of mankind, IF it is used constructively.
On the other hand, if used destructively, it will destroy just as readily. In this statement may be found a very significant truth, namely; that those who go down in defeat, and end their lives in poverty, misery, and distress, do so because of negative application of the principle of auto-suggestion.
The cause may be found in the fact that ALL IMPULSES OF THOUGHT HAVE A TENDENCY TO CLOTHE THEMSELVES IN THEIR PHYSICAL EQUIVALENT"