According to Thomas A. Bailey what does “stark but reassuring order in the divine plan” mean? I am reading “The American Pageant” by Thomas A. Bailey https://en.wikipedia.org/wiki/Thomas_A._Bailey. Bailey has given a short introduction of Calvinism. 


  Calvin argued, was all- powerful and all-good. Humans, because of the
  corrupting effect of original sin, were weak and wicked. God was also
  all-knowing—and he knew who was going to heaven and who was going to
  hell. Since the first moment of creation, some souls—the elect—had
  been destined for eternal bliss and others for eternal torment. Good
  works could not save those whom “predestination” had marked for the
  infernal fires. 
  
  But neither could the elect count on their predetermined salvation and
  lead lives of wild, immoral abandon. For one thing, no one could be
  certain of his or her status in the heavenly ledger. Gnawing doubts
  about their eternal fate plagued Calvinists. They constantly sought,
  in themselves and others, signs of “conversion,” or the receipt of
  God’s free gift of saving grace. Conversion was thought to be an
  intense, identifiable personal experience in which God revealed to the
  elect their heavenly destiny. Thereafter they were expected to lead
  “sanctified” lives, demonstrating by their holy behavior that they
  were among the “visible saints.” 
  
  These doctrines swept into England just as King Henry VIII was
  breaking his ties with the Roman Catholic Church in the 1530s, making
  himself the head of the Church of England. Henry would have been
  content to retain Roman rituals and creeds, but his action powerfully
  stimulated some English religious reformers to undertake a total
  purification of English Christianity. Many of these “Puritans,” as it
  happened, came from the commercially depressed woolen districts (see
  p. 28). Calvinism, with its message of stark but reassuring order in
  the divine plan, fed on this social unrest and provided spiritual
  comfort to the economically disadvantaged.


Well, "the American pageant" is an American high school history textbook. I am teaching this book to my students. The quote is from chapter 3 under the section title "The Protestant Reformation Produces Puritanism". The whole chapter can be read here. https://wchs.pasco.k12.fl.us/wp-content/uploads/wchs/2012/05/American-Pageant-CH-3.pdf

I need help interpreting the part in bold. I think "divine plan" means “predestination”.But what does "order" mean here?
First thing we need to establish is what the Divine Plan is.  Predestination is certainly part of it but it also has to do with redemption and salvation. “In him [Christ Jesus] we have redemption through his blood, the forgiveness of sins” (Ephesians 1:7).  Here is a brief Reformed Protestant view:

Salvation is entirely the work of God and since the plan of salvation was conceived before Adam and Eve were created, then it is entirely proper to conclude that there is divine order at work.  The Bible demonstrates God’s sovereignty and shows that nothing happens that God does not ordain, cause, or allow.  The Creator God is not a God of disorder (1 Corinthians 14:33) but is a God of order.

First, within the Godhead, the divine plan of salvation is agreed.  Second, the divine plan is executed when Christ Jesus willingly gave up his life in order to atone for the sins of the world.  Third, the divine plan is to this day seeing fulfilment in the lives of believers who have come to saving faith through the good office of the Holy Spirit.  Nothing was left to chance.  Everything necessary was planned in advance and all three parties were in agreement.  And because God is Sovereign and Omnipotent, and because Christ Jesus was resurrected from the dead (as part of that divine plan), then the outcome is assured.

That’s the good news.  That’s the reassuring part of the divine plan.  The bad news (the stark reality) is that those who reject the means by which salvation can be granted are also part of the divine plan.  They are deemed to be eternally lost – which is the opposite of being eternally saved.

The article in the link below has this to say about Calvin’s third book - The Mode of Obtaining the Grace of Christ. The Benefits It Confers and the Effects Resulting from It: 


  God’s predestination is sovereign and independent of foreknowledge, and His election is eternal. Men’s claim that predestination is unfair merely exposes their inability to understand God. All those who are predestined will be called by God and will have faith. The final resurrection will be physical for both the elect and the reprobate. Hell is real and eternal.  Source: https://www.gotquestions.org/John-Calvin.html


It’s not so much Calvin’s “message of stark but reassuring order in the divine plan” as it is God’s message to humanity regarding the stark consequences of rejecting the divine plan of salvation.  That the divine plan of salvation is ordered by God is plain to see from what the Bible tells us about the life, death and resurrection of Christ Jesus, who gave up the glory he shared in heaven in order to dwell with us and to do the will of the Father who had sent him.