Source identified1
“He that is down needs fear no fall; He that is low, no pride; He that is humble ever shall Have God to be his guide.”
The shepherd boy’s song presents lowliness as freedom from the anxieties attached to status and pride, joining humility with contentment inside Bunyan’s Christian pilgrimage allegory.
Source note: The Pilgrim’s Progress, Part II, Valley of Humiliation, Project Gutenberg #131. Mr. Great-heart and the pilgrims hear a shepherd boy sing the stanza; the line is therefore structured as fictional/allegorical character speech rather than Bunyan autobiography.