And they that understand among the people shall instruct many... Daniel 11:33
This is what a secular source has to say....
"....we need to ask when and why did parents, communities, and governments come to see it as necessary for everyone to learn to read. Here, a puzzle about neuroscience and cognition turns into a 
historical question.
Of
course, writing systems are thousands of years old, found in ancient
Sumer, China, and Egypt, but in most literate societies only a small
fraction of people ever learned to read, rarely more than 10 percent.
Q: So, when did people decide that everyone should learn to read? Maybe it
came with the rapid economic growth of the 19th century? Or, surely, the
intelligentsia of the 18-century Enlightenment, imbued with reason and rationality, figured it out?
A: No,
it was a religious mutation in the 16th century.
After bubbling up
periodically in prior centuries, the belief that every person should
read and interpret the Bible for themselves began to rapidly diffuse
across Europe with the eruption of the Protestant Reformation, marked in
1517 by Martin Luther’s 
delivery of his famous 95 theses.
Protestants
came to believe that both boys and girls had to study the Bible for
themselves to better know their God.
In the wake of the spread of Protestantism, the literacy rates in the
newly reforming populations in Britain, Sweden, and the Netherlands
surged past more cosmopolitan places like Italy and France. Motivated by eternal salvation, parents and leaders made sure the children learned to read.
The Science Confirms the History
The sharpest test of this idea comes from work in economics, led by
Sascha Becker and Ludger Woessmann.
The historical record, including
Luther’s own descriptions, suggest that within the German context,
Protestantism diffused out from Luther’s base in Wittenberg (Saxony).
---Using data on literacy and schooling rates in 19th-century Prussia,
Becker and Woessmann first show that counties with more Protestants
(relative to Catholics) had higher rates of both literacy and schooling.
So, there’s a correlation.
---Then, taking advantage of the historical
diffusion from Wittenberg, they show that for every 100 kilometers
traveled from Wittenberg, the percentage of Protestants in a county
dropped by 10 percent. Then, with a little statistical razzle-dazzle,
this patterning allows them to extract the slice of the variation in
Protestantism that was, in a sense, caused by the Reformation’s ripples
as they spread outward from the epicenter in Wittenberg. 
---Finally, they
show that having more Protestants does indeed cause higher rates of
literacy and schooling. All-Protestant counties had literacy rates
nearly 20 percentage points higher than all-Catholic counties.
---Subsequent work focusing on the Swiss Reformation, where the epicenters
were Zurich and Geneva, reveals strikingly similar patterns.
---In Africa, regions with early Protestant missions at
the beginning of the 20th century (now long gone) are associated with
literacy rates that are about 16 percentage points higher, on average,
than those associated with Catholic missions. In some analyses,
Catholics have no impact on literacy at all unless they faced direct
competition for souls from Protestant missions.
---These impacts can also
be found in early 20th-century China." Nautilus