Jesus said he will lose none of those the Father gives him and that no one can snatch them out of his hand (John 6:37–39; 10:28–29). The wording in Matthew 7 is “I never knew you,” not “I once knew you and then stopped.” Genuine belief that God raised Jesus from the dead and confession of him as Lord places a person among those the Father draws and the Son secures. That person cannot later be reclassified as never known.
Hebrews 6 and 10 remain real warnings against final, deliberate rejection after the truth has been clearly tasted and seen. They mark the finality of refusing the light. They do not override the security of those who believe and confess. The warnings instruct and rebuke. They do not create a path from belonging to being cut off. Paul describes the ongoing struggle that remains inside the believer (Romans 7) and then declares there is no condemnation for those who are in Christ Jesus (Romans 8:1).
Fruit and obedience are the right way to live and the proper response to grace. They are not the condition that places a person in Christ or keeps them there. I am a sinner. I am not going to pretend I am not. Once saved always saved. Readers can examine the passages. They can disagree. The claim is that the text keeps belonging and performance distinct.