Nature of salvation in the Old Testament [duplicate]

Question

Possible Duplicate:
Who saved people before ~33AD?

(This question I address to those Christians who believe that salvation once acquired cannot be lost. I am specifically after the answer to the following question from that perspective)

I have always thought of salvation in the New Testament as of having the eternal life. In the New Testament we are told by John that we can get this eternal life by means of believing into the Only-begotten Son of God Jesus Christ:

For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. (John 3:16)

These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God. (1st John 5:13)

However, when I am trying to look at the nature of the concept of salvation in the Old Testament, I get a bit confused about the concept of salvation that had place at those times.

First of all, the Old Testament people, of course, didn't have any knowledge of the existence of the Only-begotten Son of God and almost all of them died before this knowledge of Him was given to the human kind. However, it seems that some of them still were saved even though they died before Jesus' first coming:

There shall be weeping and gnashing of teeth, when ye shall see Abraham, and Isaac, and Jacob, and all the prophets, in the kingdom of God (Luke 13:28)

From this verse we can say that at least Abraham, Isaac, Jacob and all the prophets were saved even before Christ's crucifixion (I take it as an axiom that anyone who has the right to be in the kingdom of God is a saved person).

Now the question is at what point of their life were they acquiring that salvation? It seems that in the New Testament this point of time in people's lives is kind of more spelled out - the moment when people turn to Christ in their hearts while hearing the Gospel and pray to Him for the first time, but what about the Old Testament? At what moment of their life it was clear that they were also among those who would enter in the future into the kingdom of God (which means they were also among those who are saved)?

Answer 1

From a Reformed perspective, we look at the Old Testament promises, and the respondents' trusting God as what qualifies them as righteous and grants salvation.

God chose Abraham and made a covenant with Him (a series of 3 promises you can read in Genesis 21). Abraham believed God, and it was credited to him as righteousness.

Isaac was the son of the promise. He was obedient and faithful to his father and God by willingly laying on the altar at Moriah (Abraham was a really old dude at this point, and it's pretty unreasonable to assume that Isaac was powerless to at least escape this sacrifice, if not overpower Abraham).

Jacob was the son of the promise. His act of faith was recorded with his actions on his deathbed, that he blessed Joseph's sons with the promise of God.

Joseph was the son of the promise. His faithful acts delivered Israel in a time of famine, and lead to Moses leading the people out of Egypt so that God would display His power to His people.

This list goes on. It isn't that each of these men was sinless and trusted Christ, it's that each one was sinful and trusted God in His word that He would bless them (and no small part of that blessing is that they have been included in the bloodline of the Messiah).

Over time, we begin to understand more of the promise. The author wrote concerning this in 2 Samuel 7:12-17. This is a continued promise that God will establish David's kingdom forever and will claim father-hood over this line of people. Isaiah later writes concerning that God's people would "know His name" and God would grant salvation to all ends of the Earth through the Messiah.

Today, it has been revealed that Christ was the fulfillment of the promise to Abraham and that being a "son of the promise" was not fleshly, but spiritual, trusting God. Because it has been revealed that Christ was the fulfillment of the promise, by placing faith in Christ, you trust that God has taken care of your sins on His own account and you are adopted as a son of God and are covered by the promise that God made to Abraham. You are saved the same way that Abraham was saved: by believing God (and, as James 2 would add, demonstrating that belief in your actions).