Two versions of something short and memorable that are the almost the same is not therefore proof of literary dependence. Then give the trembling penitents each a sheet of paper. They write, in shaky hand, the Lord's saying.
True illiterates are absent from Christian history.
They could hear texts read aloud and pay to have stuff written down by the local squalid professionals who made their denarii by so doing. Several illiterates pool their intellectual and financial resources and get a scribe to write down the stuff they can think of.