General Information:

This is the beginning of a new part of the story that runs through Matthew 22:46, which tells of Jesus ministering in Judea.

These verses provide background information of how Jesus came to be in Judea. (See: rc://en/ta/man/translate/writing-background)

It came about that when

This phrase shifts the story from Jesus' teachings to what happened next. AT: "When" or "After"

Here "words" refers to what Jesus taught starting in Matthew 18:1. AT: "had finished teaching these things" (See: rc://en/ta/man/translate/figs-metonymy)

"walked away from" or "left"