What is the subject of the hymn that opens "Down at the Cross"? How does this quote tie in with the essay's themes?

The second quotation is an expression of what the author maintains throughout the book is the subjugation of the Negro spirit to white spirituality - essentially, the teachings of the Christian church. The hymn is apparently a spiritual song of both suffering and hope defined by the exclusively, uniquely Negro experience but expressed - and here is the point - in Christian terms.