“Falling from Grace” is only used once in the Holy Bible and you will find it’s use in Galatians 5:1-5 (ESV),
For freedom Christ has set us free; stand firm therefore, and do not submit again to a yoke of slavery.
2 Look: I, Paul, say to you that if you accept circumcision, Christ will be of no advantage to you. 3 I testify again to every man who accepts circumcision that he is obligated to keep the whole law. 4 You are severed from Christ, you who would be justified by the law; you have fallen away from grace.5 For through the Spirit, by faith, we eagerly wait for the hope of righteousness. 6 For in Christ Jesus neither circumcision nor uncircumcision counts for anything, but only faith working through love.
Paul was writing in regards to those who were turning law-works into something that was saving them from “falling away from grace.” This is not about someone losing their salvation. Again context is a mighty thing when reading scripture.