
The Bible is accused of being the source of many things. Here is one that doesn't come from the Bible: we can turn our backs on God.
False readings with legalistic biases assume that a passage like the prodigal son are about a Christian turning from God and then turning back to Him. While this is commonly understood it is as wrong as saying the moon is made of swiss cheese.
The Bible is non-contradictory. One teaching can't logically oppose another and have both be true at the same time for the same people. God just doesn't operate like that since he made us and knows that that would make it even more difficult than it is to understand Him.
The Prodigal Son story explains how gentiles first came to Christ. So the story is actually more about the anger "other son" that doesn't like the newcomer. At the beginning of the story, both sons were living at home. That was , in the metaphor of the story, the time early in the world when there really weren't other people than Noah's family. Then, one son leaves, and thus the gentiles are born. Under Christ there is no gentile, but perhaps even more importantly, there IS NO JEW. There is just one family of God. Ethnically there are of course Jews, but not spiritually any different from the gentiles, since Christ's gift of salvation is the same for all.
Once the Prodigal Son returns, does he ever leave again? No
Once you are in Christ is it even possible to leave? No
Can one "fall from Grace"? No
So, as the picture indicates, you are safe and the world is one big Gorazde.
AK