Like Job, Israelites living during the Old Testament times, before the second temple, knew they were mortal and would die. Buried in the earth, they would become part of it. They, along with Job, had faith in a physical resurrection, into a kingdom ruled by their righteous God. In this kingdom they would see their redeemer with their own eyes of flesh. 

Job 19:25-26 The Voice

25 Besides, I know my Redeemer lives, and in the end He will rise and take His stand on the earth. 26 And though my skin has been stripped off, still, in my flesh, I will see God.

Although they expected to be raised to a physical life when God set up his earthly kingdom, God also gave them hope of gaining immortality if they lived a Godly life.

Proverbs 12:28

New International Version

28 In the way of righteousness there is life; along that path is immortality.

Daniel 12:1-3 Living Bible

1 “At that time Michael, the mighty angelic prince who stands guard over your nation, will stand up and fight for you in heaven against satanic forces, and there will be a time of anguish for the Jews greater than any previous suffering in Jewish history. And yet every one of your people whose names are written in the Book will endure it.

2 “And many of those whose bodies lie dead and buried will rise up, some to everlasting life and some to shame and everlasting contempt.

3 “And those who are wise—the people of God—shall shine as brightly as the sun’s brilliance, and those who turn many to righteousness will glitter like stars forever.

In this predicted future coming kingdom of God, each person is rewarded for who they are. There will be evil ones who reject the lifestyle of God and with it, immortality. Their shameful rejection of God will be their legacy. Those who willingly embrace their God of love in righteousness, will live with him eternally.

Do these Old Testament prophecies of immortality surprise you? When immortality is a future promise, how could humans already possess it in the form of an immortal soul? Can God give us something we already have?