The gospel has foretold that there will be people who call themselves believers who would be like this:
Matthew 7:21-27
21 ‘Not everyone who says to me, “Lord, Lord”, will enter the kingdom of heaven, but only one who does the will of my Father in heaven. 22On that day many will say to me, “Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many deeds of power in your name?” 23Then I will declare to them, “I never knew you; go away from me, you evildoers.”
Hearers and Doers
24 ‘Everyone then who hears these words of mine and acts on them will be like a wise man who built his house on rock. 25The rain fell, the floods came, and the winds blew and beat on that house, but it did not fall, because it had been founded on rock. 26And everyone who hears these words of mine and does not act on them will be like a foolish man who built his house on sand. 27The rain fell, and the floods came, and the winds blew and beat against that house, and it fell—and great was its fall!’
Case in point they were never believers. And thus not under grace.