The grace of God is a complete job from beginning to end.
The grace of God is a complete job from beginning to end. So, what does Paul mean by "fallen from grace"? Falling from grace occurs when you cease to believe that only God's grace can save you. You are falling away from grace when you trust in some external rule or some man-made ritual or church dogma to get you to heaven. When you add something to the grace of God to receive the favor of God, you are falling from grace. It can happen easily, so we must be on guard. We can begin to turn our good works done out of gratitude to God into a means of paying Him back, which is a mockery of the Gospel.
To fall from grace is to fall into legalism. Legalism says that you are not saved by God's grace alone, but rather, you are saved by God's grace and your success at keeping rules. In choosing legalism you have turned away from the all-sufficient grace of God for salvation.
When you teach that salvation is through grace plus something—whatever that something is—you repudiate the whole Gospel of Jesus Christ. If a person is trying to be saved by works, that person has fallen from grace into legalism and therefore cannot be saved at all, for Jesus is the only Savior: "There is no other name under heaven given to mankind by which we must be saved" (Acts 4:12). And even our faith is a gift from God and not our own work so that no one can boast in anything other than Christ (see Ephesians 2:8-10). Legalism is man's way, not God's way.
Prayer: Father, help me remember that it is only by Your grace that I am saved. Give me the wisdom to discern those times when I begin to add to Your Gospel for my salvation and to repent and rest in Your finished work of salvation. I pray in the name of Jesus. Amen.
"You who are trying to be justified by the law have been alienated from Christ; you have fallen away from grace" (Galatians 5:4).