MENSCHEN, DIE NICHT ZWISCHEN RECHTS UND LINKS UNTERSCHEIDEN KÖNNEN

MENSCHEN, DIE NICHT WISSEN, WAS RECHTS UND LINKS IST
This is the Luther version of the Jonah reference to children and/or infidels as "persons who cannot discern between their right hand and their left."
people who cannot tell their right hand from their left
Their ignorance is so great they “cannot tell their right hand from their left.” 
Luther says "rechts und links" in a more abstract sense.
Another German translation says "Menschen, die rechts und links nicht unterscheiden können."
Or "Menschen, die nicht einmal rechts und links unterscheiden können."
Or "Menschen, die nicht zwischen rechts und links unterscheiden können."

people who do not know

the difference between their right hand and their left,

ORDINARY GLOSS:

We can understand this with

regard to the age of infancy, which is innocent and simple, and

 the number of little ones is so great,

who, before doing penance, did not know the diference between good and evil. 

Again, in my Othello essay "The Rightful Left-tenant" (which can be found on this blog), I discuss this biblical reference and correlate it to the Japanese idiom "migi mo hidari mo wakaranai (右も左もわからない)." As well as to Cassio's left-right confusion (and it tells a lot about left-right symbolism in Othello, btw).
Luckily for me, I wore conveniently colour-coded Kickers as a child...

Kickers: green for right and red for left.

Wherein are more than six score thousand {persons), 

that are so young, and voide are of all {reason), 

that by no means they able are to learne, 

the right hand from the left, for to discerne ? 

Should I subvert so many infants too?

Earbuds are usually marked with the letters L and R. So you know which one goes where.

Knowledge of the left-right distinction is considered a sign of maturity: I myself learned the difference upon hitting puberty, i.e. that my left faces the right of what I see through my eyes and vice versa. Before that, I thought that the left was always the side of my writing hand and the two/three birthmarks on my forearm. One of the ways I learned real left-right distinction was through the clever use of colour-coded Kickers shoes: red for left and green for right. Thus, I learned that my left side faces the right side of others and vice versa. The gunshot on Lord Nelson's left shoulder at Trafalgar and my handedness and birthmarks, however, proved more influential in this aspect than the Kickers; from looking at depictions of the dying admiral, I realized that my right faced Horatio's (and everyone else's) left.