Some would say that “grievous” (stern NASB) (7451a) “correction” (discipline NASB) (4148) is just the method God uses to bring believers back into fellowship. There is a spiritual condition that would fit that idea. There is the place for reproof and rebuke. We have I John 1:9, written to believers.
(1 John 1:9 KJV) If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.God is able to read our hearts and respond accordingly. Just as you would not respond to a clumsy three year old who breaks a plate the same way you would to an eighteen year old who threw one at the cat, God is capable of seeing the nuances of sin.
Having said that, this seems a little bit stronger than immaturity or a flash of anger. “Forsakes” (5800) does not sound like being in grace but out of fellowship. This is the condition of someone who has made a conscious decision to walk away from God and His way of living. A husband and father who forsakes his family is not just late for dinner.
Stern discipline is for one who “hates” (8130) the spiritual process of “reproof” (8433b). You can follow this in the NT. Mature believers are to reprove and rebuke. They are to correct. It is part of being the family of God, just as it is part of a family. One who “hates” (8130) correction cannot be a believer.
This attitude means you will “die” (4191). This is not just the breaking of fellowship, it is an ending. This is why it is important to have the right faith. The wrong belief can send you to hell, not because you are wrong on a detail, but because it leads you to live in such a way that heaven is ruled out.
So? This is pretty basic. God does not play games. He knows what we think and what we feel. This means, unlike us, He does have the right to judge. This is a simple caution not panic mode. Walk in faith. Live in obedience. Trust Him for your salvation.