Many times it is claimed by us Christians in the Old Testament age, before Christ, God did not inspire the love for His son Jesus in the hearts of men. He had not yet come, and therefore, how can one believe in Him?
So, the conclusion reached is that either everyone who died in the days before Christ are condemned, or God saved them by a path other than Christ (faith in the Father alone? By sacrifice? By obedience?).
Of course, we know that neither is true. Paul notes, in Romans 3:25-26:
"God presented Jesus as a sacrifice of atonement, through faith in His blood. He did this to demonstrate His justice, because in His patience he had left the sins committed beforehand unpunished - he did it to demonstrate His justice at the present time, so as to be both just and justifier..."
So clearly, not everyone who died in the Old Testament Age went to Hell! But with the same token, it didn't happen by a "third" path.
"Salvation is found in no one else, for there is no other name under heaven given to men by which we must be saved."
So, the only conclusion left is that faith in Christ was possible in the times before Christ. We see notable indications of this in the lives of Abraham (John 8:56, Romans 4:18) and Isaiah (John 12:41, Isaiah 53) - however, the Lord sometimes indicates Jesus to the Old Testament folk in a more subtle way. Consider this selection from Hosea:
"Therefore, I am now going to allure [Israel],
I will lead her into the wilderness*
and speak tenderly to her.
There I will give her back her vineyards
and will make the Valley of Achor a door of hope
There she will sing as in the days of her youth
as in the day she came up out of Egypt
In that day, declares the Lord,
you will call me "my husband"**
you will no longer call me "my master"
I will plant her for myself in the land;
I will show my love to the one I called
'Not my loved one.'
I will say to those called 'Not my people,'
'You are my people.'***
And they will say, "You are my God."
*For me, this echoes the strains of Isaiah 40:3, seen in the New Testament in Matthew 3:3 and especially Luke 3:4-6.
**Christ is called the husband of the church (Ephesians 5:23), in Heaven the church is called "the bride and wife of the Lamb" (Revelations 21:9), all of marriage and indeed the culmination of sex in orgasm is just a weak illustration of the joy between husband and wife, Christ and church.
***Galatians 3:28 states that even the Gentiles, despised and condemned by Jews of the OT age as unclean and abhorrent are only in Christ united with Jews themselves - and slave, and freeman, and woman and female, tall and short; everyone is equal in Christ.