Mate I have to be honest I have no idea what heresy is. I researched it and can't come to a conclusion on its meaning and consequences.
Ok, that's fair.
The Strongs doesn't give much to work with, and I suspect the modern meaning may have evolved since those days, as I'm sure Paul, who warned us about these last days and the many false doctrines that we would encounter, didn't have specific knowledge of each and every one, but more of a general knowledge that...in latter times some will depart from the faith, giving heed to deceiving spirits and doctrines of demons,2 speaking lies in hypocrisy, having their own conscience seared with a hot iron, 1 Timothy 4:1-2
By contextual definition, a doctrine that causes someone to depart from the faith, which is the point of this thread that Jethro started, and is about false doctrine that causes folks to stumble, which as you can see from the many post's, means among other things, to fall away, or depart from Christ; ie: fall into deception.
The OSAS doctrine teaches that a person needs no longer, to continue to have faith in Christ, to remain saved.
The Holy Spirit says... Now the Spirit expressly says that in latter times some will depart from the faith, giving heed to deceiving spirits and doctrines of demons, 1 Timothy 4:1
A teaching that causes a person to depart from the faith, is a doctrine of demons, that comes from deceiving spirits, and not the Spirit of Christ.
That would be a good start as to what heresy is.
To be honest, just because a person says that another is teaching heresy, does not necessarily mean they are indeed teaching heresy.
I hope as to the consequences, you can see what that is from Galatians 5:19-21
19 Now the works of the flesh are evident, which are: adultery,fornication, uncleanness, lewdness, 20 idolatry, sorcery, hatred, contentions, jealousies, outbursts of wrath, selfish ambitions, dissensions, heresies, 21 envy, murders, drunkenness, revelries, and the like; of which I tell you beforehand, just as I also told you in time past, that those who practice such things will not inherit the kingdom of God.
Galatians 5:19-21
Do you understand this phrase, as to what "will not inherit the kingdom of God" means?
In addition, Paul associates heresy with sorcery, sexual immorality.
Here is another place Paul uses this phrase.
9 Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived. Neither fornicators, nor idolaters, nor adulterers, nor homosexuals, nor sodomites, 10 nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners will inherit the kingdom of God. 1 Corinthians 6:9-10
fornicators
idolaters
adulterers
homosexuals
sodomites
These are among those who will not inherit the kingdom of God.
Those Christians who repent and turn from these things, will be forgiven by our merciful Savior, but those who continue to practice these things, and die unrepentant of these things, will not inherit the kingdom of God.
JLB