Nobody is actually saved yet fully, our body is still in bondage to corruption for one. Salvation is in Christ, the reason the Bible talks about salvation in the present sometimes (not always) like ye HAVE eternal life, is because these people are abiding in Christ.
Eternal life is in Christ (John 15) and those who abide in Him, have eternal life. The ones who do not abide in Christ do not have eternal life.
That is why the Bible also speaks of eternal life in the future tense (often overlooked in churches today). "In the HOPE OF eternal life".
Hebrews 3:14 For we are made partakers of Christ, if we hold the beginning of our confidence stedfast unto the end;
This is the case for every OSAS proof-text, you look around the context and look look! There is the condition for it. That is a great exercise I wish everyone would do, go read all the proof-texts for OSAS and then look around the context, surrounding chapters and verses and it will quickly reveal the truth of the matter. (Unless you got itching ears and don't want to hear it, that is)
One example:
Colossians 1:20-23
And, having made peace through the blood of his cross, by him to reconcile all things unto himself; by him, I say, whether they be things in earth, or things in heaven.
And you, that were sometime alienated and enemies in your mind by wicked works, yet now hath he reconciled
In the body of his flesh through death, to present you holy and unblameable and unreproveable in his sight:
If ye continue in the faith grounded and settled, and be not moved away from the hope of the gospel, which ye have heard, and which was preached to every creature which is under heaven; whereof I Paul am made a minister;
See there, it says reconciled all things unto himself, we have been reconciled now (PAST TENSE) therefore its a done deal! Once born again you cant be unborn again! DUH! Or are you saying God is too weak to save you? You need to be a co-savior? We know all the arguments, dont you worry! But then the next verse hits, IF ye continue in the faith.
The same thing with John 10:27. The sheep are supposed to FOLLOW HIM. If that is what the OSAS people preached, I would agree with them. AMEN! Sheep shall never perish and Jesus gives them eternal life, and they follow Him! Nothing shall take them.