Prior to the cross, Mary, the mother of Jesus believed in the Savior of the OT who would come to save her from her sins....
Luk 1:46,47 - And Mary said, "My soul magnifies the Lord, and my spirit rejoices in God my Savior,
Of the OT writers believed that they needed a savior and looked forward to a day when that would become a reality.
Both the OT and the NT remnant lived by faith in the promise of salvation to all who believe.
SAMUEL:
2Sa 22:3 - "...my God, my rock, in whom I take refuge, my shield and
the horn of my salvation, my stronghold and my refuge,
my savior; thou savest me from violence.
PSALMS: (David, Moses et al)
Psa 106:21 -
They forgot God, their Savior, who had done great things in Egypt,
ISAIAH:
Isa 19:20 - It will be a sign and a witness to the LORD of hosts in the land of Egypt; when they cry to the LORD because of oppressors
he will send them a savior, and will defend and deliver them.
Isa 43:3 -
For I am the LORD your God, the Holy One of Israel, your Savior. I give Egypt as your ransom, .
Isa 43:11 -
I, I am the LORD, and besides me there is no savior.
Isa 45:15 -
Truly, thou art a God who hidest thyself, O God of Israel, the Savior.
Isa 45:21 - ...And there is no other god besides me,
a righteous God and a Savior; there is none besides me.
Isa 49:26 - "...Then all flesh shall know that
I am the LORD your Savior, and your Redeemer, the Mighty One of Jacob."
Isa 60:16 - "...
and you shall know that I, the LORD, am your Savior and your Redeemer, the Mighty One of Jacob.
Isa 63:8 - For he said,
Surely they are my people, sons who will not deal falsely; and he became their Savior.
JEREMIAH:
Jer 14:8 -
O thou hope of Israel, its savior in time of trouble, why shouldst thou be like a stranger in the land,...
HOSEA:
Hosea 13:4 -
I am the LORD your God from the land of Egypt; you know no God but me, and besides me there is no savior.
Even before Adam and Eve had children, God promised salvation to all believing mankind in
Genesis 3:15...
"I will put enmity between you and the woman, and between your seed and her seed;..." When they did have children, we see the first written instance of sacrifices being presented to God which would indicate future forgiveness for all who believe in that promised
"seed" which would be called
"the Messiah/Emmanuel."
Now when Cain and Abel were old enough to bring sacrifices to the Lord, we see this account in Genesis 4:2-4...
"Abel was a keeper of sheep, and Cain a tiller of the ground. In the course of time Cain brought to the LORD an offering of the fruit of the [cursed]ground, and Abel brought of the firstlings of his flock and of their fat portions. And the LORD had regard for Abel and his offering,"
LONG before Noah, and before Abraham was called out of a GENTILE nation, at the very beginning of history as we know it, God always provided a way for man to receive forgiveness!