Heb 10:35 Cast not away therefore your confidence, which hath great recompence of reward.
Heb 10:36 For ye have need of patience, that, after ye have done the will of God, ye might receive the promise.
Either purification isn't instant but requires that you stay the course and carry your cross, or salvation isn't instant but requires that you stay the course and carry your cross. It can't be that both are instant in light of , "... that, after ye have done the will ..." because something is your only after you've done His will.
I have to wear braces like gloves with the fingers cut out to type some days so if you could ignore the typos I'd appreciate it. I did see that one just as I hit the “post”, though.
Salvation is instant upon conviction that Jesus is the only way and acceptance of Him as your only salvation. Belief in self works to maintain that is lack of faith in that perfect and sufficient sacrifice. The only way to lose that salvation is to no longer believe that Jesus paid the COMPLETE once for all time penalty for all sin or completely renounce that faith in Jesus complete and only sacrifice for all sin.