Re: OSAS And 1 Tim. 4:1 I believe that one can backslide and be lost like Judas if they don’t continue in the faith . Remember, this is a race and those that endure till the end will be saved. Judas was written in the book of life but was blotted out, whereas Peter backslid then repented was restored and found salvation through the new birth. Read Luke 10:17-20. Matthew 26: 69-75 and 2Tim.4:6-9. And what of all those we know that have left their faith and no longer serve Christ but live ungodly lives but still believe in Christ are they still saved?
John 17:12 indicates that Judas was never saved. Jesus picked him so the prophecies of His betray could be fulfilled (Matt. 26:24, John 6:70). Therefore Luke 10:17-20 cannot apply to him.
As for Matt. 26:69-75, the Lord knew in advance that Peter would stumble and would be restored (Luke 22:30-32). In John 17:12 before Peter denied Him, Jesus said He hadn’t lost any of the disciples except Judas and that includes Peter.
In 2 Tim. 4:6-9 Paul was talking about the crown of righteousness he would qualify for, not his salvation. He said the same thing in 1 Cor. 9:24-27 about the crown of victory. The race we run is for crowns and only those who qualify by having already been saved can enter. We know this because in Ephes 1:13-14, 2 Cor. 1:21-22, and Romans 8:38-39 Paul wrote that our salvation is guaranteed by God from the moment we believe and no power in heaven or on earth can change that.
The context of Matt. 24 shows that the Lord’s phrase, “He who stands firm to the end will be saved” (Matt. 24:13) applies to Tribulation believers, who will not be given the blessing of eternal security that the Church enjoys. The Lord explained this statement in more detail in the parable of the 10 virgins (Matt. 25:1-13).
Based on these things we know that during the Church Age those who have truly left the faith were never saved to begin with. John wrote that their going out proves they didn’t belong to us in the first place (1 John 2:19). But regardless of what others may think of their behavior, if they were once saved they are always saved.