Who said "A man becomes what he thinks about most of the time."?

This quote is attributed to John Steinbeck.

A man becomes what he thinks about most of the time. - John Steinbeck

"A man becomes what he thinks about most of the time."

John Steinbeck

Novelist American 1902–1968

"The person who says it cannot be done should not interrupt the person doing it."

"All war is a symptom of man's failure as a thinking animal."

"Ideas are like rabbits. You get a couple and learn how to handle them, and pretty soon you have a dozen."

"The comfortable people want only waking and sleeping, eating and excreting, working and reproducing."