When Paul wrote his letter to the Galatians, he was astonished at how quickly they had been turned by others who invaded their turf after he had been there ... and these seemed to want to distort the gospel of Christ. These Gentiles had previously been given the pure message of the grace of Jesus, but were now being told they needed to mix some aspects of the Mosaic law with faith in Christ.
Paul referred to it as a different gospel (although it was really no gospel at all). He had some strong words against those delivering this contrary message and it launched the rest of his "Galatians" letter, where he would expound on the differences between a ministry of bondage under works, compared to a New Covenant of Faith.
When someone is accused of falling from grace in today's "religiondom" (introducing a new word on the podcast!), it is usually used in the context of a person who has been caught in some sort of "major" sin or was discovered to have broken a significant commandment from the Mosaic law. Perhaps it involved a habitually failed attempt at commandment-keeping—and caught the attention of the rumor mill—also known as the judge and jury.
The phrase "fallen from grace" appears in one passage (Galatians 5:4). Even within this very Bible verse, it tells us what caused the Galatians to have fallen from grace, and it's pretty much the precise opposite of what church attendees have been told. But as we often do, we will expand the boundaries of the context to help get a clearer understanding in order to avoid the pitfall of yet another false assumption which slipped through the religious church filter.
