Many of us are familiar with the story of the Prodigal Son. But how about the story of the Prodigal Pig? That is in the Bible too:
For it would have been better for them not to have known the way of righteousness, than having known it, to turn from the holy commandment delivered to them. But it has happened to them according to the true proverb: "A dog returns to his own vomit," and, "a sow, having washed, to her wallowing in the mire." (2 Peter 2:21–22)
There are many reasons I know the Bible is true, and two of them are in the above passage. I have watched a dog return to its own vomit. If you have ever owned a dog, then you probably have too. As for pigs you can take them, dress them up, and even spray perfume on them. But the first chance they get, they will make a beeline to the mud. Why? Because a pig is a pig.
So when a person claims to be a Christian, here is how to know whether he or she really is a follower of Jesus Christ. Believers, even when they go astray, always will return to God. However, nonbelievers won't. Writing on this matter, the apostle John said, "They went out from us, but they were not of us; for if they had been of us, they would have continued with us; but they went out that they might be made manifest, that none of them were of us" (1 John 2:19).
So when we look at people who seem as though they have fallen away from the Lord, and we wonder whether they have lost their salvation, I suggest the possibility they were not even saved to begin with. Because the true test is where you end up.