(I send this forth in all sincerity and with the kindness of Christ. If you disagree, please respond graciously also. Let’s see if Godly people can have a serious and Christ-honoring discussion about this hotly debated subject. Thank you.)
Let me set the table with something the Lord Jesus said. When the disciples returned from preaching with glowing reports of amazing victories over the devil, our Lord called them back to earth, so to speak, with this:
“Do not rejoice because the spirits are subject to you. But rejoice because your names are written in heaven” (Luke 10:20).
See what He did there? The Lord changed the basis of their joy and thanksgiving from something that fluctuates–like the visible results of missions, which can be good or bad, up and down–to something permanent, our salvation.
Jesus thought our salvation was secure. Otherwise, wouldn’t He have chosen some other basis for our joy?
No other conclusion is possible. Jesus clearly thought salvation was a one-time-and-done proposition. Something permanent, solid, irreversible.
As far as I am able to tell, you will not find one place in the utterances of the Lord Jesus that say otherwise.