OSAS

Is once saved always saved a true doctrine or is it so that those have have been eternally saved can lose their salvation? What does the bible say?

(Romans 8:28-31 [KJV])
 [28] And we know that all things work together for good to them that love God, to them who are the called according to his purpose.
 [29] For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren.
 [30] Moreover whom he did predestinate', them he also called: and whom he called, them he also justified: and whom he justified, them he also glorified.
 [31] What shall we then say to these things? If God be for us, who can be against us?

Notice above that there is a one to one relation between those that God the Father foreknow [29] and those that are glorified [30]. Indicating that everyone that has been foreknown by God the Father will also go to heaven, that is be glorified, and the scripture cannot be broken.

So this proves beyond a shadow of a doubt that the doctrine once saved always saved is true for the saints.

Also we see that there is a one to one relation between those that God the Father foreknow [29] and those that he called [30] and that all things work together for good to them that are called [28]. So therefore also we see that all things work together for good to the saints.

(Hebrews 7:25 [KJV]) Wherefore he is able also to save them to the uttermost that come unto God by him, seeing he ever liveth to make intercession for them.

We see also above that Jesus Christ is able to save to the uttermost those who come unto God by Jesus Christ.