We do not always remember the day or the hour that God saved us when we believed in Him, however, we do remember that we were changed entirely.
Our hearts were changed into a new creation. Our actions and reactions were completely different from what we used to be in our old man.
2 Corinthians 5:16-18 "…16 So from now on we regard no one according to the flesh. Although we once regarded Christ in this way, we do so no longer. 17 Therefore if anyone is in Christ, he is a new creation. The old has passed away. Behold, the new has come! 18 All this is from God, who reconciled us to Himself through Christ and gave us the ministry of reconciliation:…"
After declaring that they decided to become a Christian, those who have had no change in their hearts were never born again. Those who rage against God's Word, even rage against fellow believers for their adherence to the scriptures, were never made a new creation.
Just deciding to join a church or say you are a Christian is not salvation. Salvation comes when we are grieved by our own sinfulness and want to be changed by Christ. Then is when we "believe", some say "trust in Christ", probably the more accurate rendering.
"Believing" is the word used in most Bibles but the connotation is beyond just a mental exercise, it is trusting in Christ.
Someone who says they are a believer but do not trust the scriptures to guide them has no desire for Christ or His principles, they remain the old man who wants to live as they please without the governing of the Holy Spirit.
No one who is born again has contempt for His Word or contempt for the brethren on any level.
1 John 3:13-15 "…13 So do not be surprised, brothers, if the world hates you. 14 We know that we have passed from death to life because we love our brothers. The one who does not love remains in death. 15 Everyone who hates his brother is a murderer, and you know that eternal life does not reside in a murderer.…"
Christians disobey from time to time, but they do not rage at someone for pointing out their sin, rather they are ashamed and turn from it eventually.
1 John 3:8-10 "…8 The one who practices sin is of the devil because the devil has been sinning from the very start. This is why the Son of God was revealed, to destroy the works of the devil. 9 Anyone born of God refuses to practice sin because God’s seed abides in him; he cannot go on sinning, because he has been born of God. 10 By this, the children of God are distinguished from the children of the devil: Anyone who does not practice righteousness is not of God, nor is anyone who does not love his brother."
Those who live in a state of continual anger, gossip, and rage at anyone they don't like are not born again. If they were born again doing it just once would convict them, cause them to repent, and attempt to make it right to heal a relationship. The worldly pretender has no conviction only wrath when confronted with their sin.
Jeremiah 6:14-15 "…14 They dress the wound of My people with very little care, saying, ‘Peace, peace,’ when there is no peace at all. 15 Are they ashamed of the abomination they have committed? No, they have no shame at all; they do not even know how to blush. So they will fall among the fallen; when I punish them, they will collapse,” says the LORD."
When we see someone who easily rages at a correction, passes on, and even devises gossip, demeans others, and calls it a joke, as well as defending their sinful superior attitude, we are observing a twisted mind full of hate. This is not a person who is born again.
Pray for these people but avoid them as much as possible, they will bring nothing but frustration as they attempt to cause us to sin by their pokes and jabs.
Proverbs 22:24-25 " 24 Do not make friends with an angry man, and do not associate with a hot-tempered man, 25 or you may learn his ways and entangle yourself in a snare.…"
The devil uses angry people to attempt to make us act in ways we would rather choose not to act. The angry person attempts to cause us to lean into the flesh as they do, then they will say; "see how you are", even though they started the whole mess. Their desire to ruin us in the eyes of everyone around us is intense and unrelenting.
If we are to obey God we will pray for them and avoid them as much as possible.