Revelation Chapter 2:2-5
2 I know thy works, and thy labour, and thy patience, and how thou canst not bear them which are evil: and thou hast tried them which say they are apostles, and are not, and hast found them liars:
3 And hast borne, and hast patience, and for my name's sake hast laboured, and hast not fainted.
4 Nevertheless I have somewhat against thee, because thou hast left thy first love.
5 Remember therefore from whence thou art fallen, and repent, and do the first works; or else I will come unto thee quickly, and will remove thy candlestick out of his place, except thou repent.
They have laboured, they have worked for God, lived for god, yet they have left thy first love. He asks for them to repent or otherwise he will come and remove the candlestick out fo his place.
If we were OSAS then there is no reason for the word REPENT to even be in the bible. If we are saved for ever then why must we repent. There would be no reason for it. Because we love God we repent? Thats exactly why we do, but there is still a purpose for repenting. We must sanctify ourselves. If we were OSAS there is no reason for sanctification. There is no reason for temptation on us by Satan, for we cannot fall and He could spend alot more time on those he could devour. We must endure til the end.
Revelation 3:5
5 He that overcometh, the same shall be clothed in white raiment; and I will not blot out his name out of the book of life, but I will confess his name before my Father, and before his angels.
So we must overcome to make it in, then we will not have our names blotted out. That means there will be some to know God then to turn from him, and have our name blotted out. I believe no man can pluck us out of the fathers hand, but we can pluck ourselves. We were given a free will by God. It's our free will that we use to choose God and to endure til the end.
Matt 7:22 "Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? 24: And then will I profess unto them, I never knew you: depart from me, ye that work iniquity."
Now in Mark 16:17 says "And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; 18: They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover."
Now when you become a believer, you repent and you ask him into your life, (translation become saved), now any true believer knows you have to be saved and have Jesus Christ in your life to cast out devils. For only in his name can this be done. So if the lord says in Matthew that he shall have people say "didnt I cast out devils in your name" and then he says for them to depart from him, do you not think that they must have been saved, performing these miracles as it says, and then they turned from him in sin, or there old ways. They must have never repented of there sins.
Matthew 10:22
"(22)And ye shall be hated of all men for my name's sake: BUT HE THAT ENDURETH TO THE END SHALL BE SAVED."