When we get into the topic of salvation there are so many possible and interesting viewpoints for it it is almost baffling.
I agree. But of course if we could see it in black and white in the bible, the viewpoints can be limited.
And here's one perspective of it. Even in the old testament times, God gives conditions for salvation:
And thou, Solomon my son, know thou the God of thy father, and serve him with a perfect heart and with a willing mind: for the LORD searcheth all hearts, and understandeth all the imaginations of the thoughts: if thou seek him, he will be found of thee;
but if thou forsake him, he will cast thee off for ever
1 Chrs 28:9
This is true even in the New Testament:
Behold therefore the goodness and severity of God: on them which fell, severity; but toward thee, goodness, if thou continue in his goodness: otherwise thou also shalt be cut off
Rom 11:22
Once a person is saved by grace, he will be saved from hellfire as well if that person continues in his goodness.
But...
For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries
Heb 10:26-27