You say Peter was preaching to those who are already saved.
Correct.
Okay then, Peter tells those who are already saved that if they are not obeying, they are in danger of losing their salvation.
As if the Holy Spirit does not convict a BELIEVER that they are doing something displeasing to the Lord and they can be helped by the Holy Spirit to stop.
No BELIEVER can lose its POSITION with Christ for SALVATION is ALL OF GOD and none of the BELIEVER.
If a BELIEVER says 'I am so afraid I did something so wrong, I think I lost my salvation.' The fact that they are worried about it will tell anyone with two cents of comprehension that that BELIEVER has NOT lost their Salvation.
A BELIEVER's POSITION with Christ NEVER changes for Jesus Christ and what He did at the Cross of Calvary NEVER changes.
A BELIEVER's CONDITION changes every single day and the Holy Spirit comes beside that BELIEVER and help him/her, Jesus said so.
That goes against your Calvinistic teachings. It also goes against faith alone madists.
Nonsense, for I am neither Calvinist or MADist. BOTH ARE SAVED, BTW.
I am BIBLEist.