What is the "gospel" in OT according to the Calvinist?

Question

This question is following my question before. At my question there I have a quotation from Reformation Study Bible (2015) :

Divine illumination and persuasion is necessary for the heart blinded by sin to respond to the gospel.

From my question there, the conclusion : "Lydia is not a believer in the sight of God when Paul walk to approach the women there" because Lydia has not hear the Gospel yet (as Paul hasn't even sit there let alone talk to the women).

Genesis 6:9(NIV)
This is the account of Noah and his family. Noah was a righteous man, blameless among the people of his time, and he walked faithfully with God.

Job 1:8 (NIV)
Then the LORD said to Satan, "Have you considered my servant Job? There is no one on earth like him; he is blameless and upright, a man who fears God and shuns evil."

1. When God declare in the verse above, are they a non-believer in the sight of God ?
   
2. what is the Good News heard by Noah and Job when they are a non-believer in the sight of God ?

This question appear because in a Christian Forum (in our mother language) I propose that Cornelius (before he met the angel, before he met Peter let alone heard the Gospel from Peter) is a believer in the sight of God, but the Calvinist in that forum say that Cornelius is not a believer in the sight of God before those events, although he worship God. The same with Lydia. Their reason : because they (Cornelius/Lydia) haven't heard the Good News yet... so, God hasn't regenerate them. Besides there is no text read that God already opened Cornelius heart before those events.

When I ask the two questions above, I get the answer which consistent with their reason ---> Noah/Job are a non-believer in the sight of God although they worship God because they haven't heard the Good News, so God hasn't regenerate them yet.

That's why I ask here to confirm.

Answer 1

One has to treat the situation of men who lived prior to the coming of Christ a little differently to those of us who live in the new covenant age after the coming of Christ.

It is certainly true that only those who believe and trust in the Lord Jesus Christ having heard the message of the gospel are saved. However my understanding of reformed soteriology is that those who lived under the old covenant were also saved by faith, in exactly the same way as those of us who believe are now. Their faith was in the coming Messiah who was revealed to them in the types and shadows of the ceremonial law and the words of the prophets.

Noah and Job were certainly Christians because they trusted and believed in the God that revealed himself to them in their own time. Paul's argument in Romans 4 sets out to show that Abraham was saved by faith because he believed God's promises. Even though Christ had not yet come and his true nature and mission were still somewhat veiled, yet what was revealed to these old covenant believers was sufficient grounds for them to believe and be saved.

Answer 2

I think you imagine all who call themselves Calvinist are identical in beliefs. I call myself Calvinist in that I believe in TULIP, but am baptist, which means some Presbyterian Calvinists would say I am not truly Calvinist. It may be better just to go with asking what does scripture teach rather than what do certain people believe.

From the beginning God revealed that one day a Saviour would come: those whose hopes relied on that and walked with God as a consequence were saved. From the very moment Adam and Eve sinned God promised a Saviour, (Genesis 3:15), and showed that faith in sacrifice and a covering (of righteousness not our own) made us right with God (Genesis 3:21).

Job had faith in a coming Saviour and he believed he would one day see him with his own eyes; i.e. he believed death is not the end but he would be raised from the dead, a personal resurrection:

"For I know that my redeemer lives, and that he shall stand at last upon the earth. And though after my skin worms destroy this body yet in my flesh shall I see God: whom I shall see for myself, and mine eyes shall behold and not another." (Job 19:25).

He is very emphatic, He believed God would one day become visible (i.e. would be made flesh) and, one day, after his death, he will be raised and shall see him.

As for Lydia and Cornelius, they were saved OT believers looking forward to the coming Messiah, with the Spirit in part, who received the fullness after hearing about our Lord Jesus.