When Jesus Christ came to earth, he came to rescue a specific number of people. In John 10:14–16 Jesus spoke about knowing his sheep intimately, and about giving his life for his sheep. Jesus did not come to rescue people in general. He did not give his life in order to make salvation possible only to find out later who his sheep were. No, he died to save his sheep. He knows his sheep and he laid down his life for them. And if those sheep are not in his fold, he goes and brings them in also.
The New Testament also refers to a famous list, the Lamb’s book of life. The Lamb's book of life lists all the elect who belong to God (Revelation 13:8; Revelation 20:11–15; Revelation 21:27), all those sheep for whom Jesus Christ came to die. Through the preaching of the gospel, Jesus Christ makes sure that all of his sheep will come to hear the good news of what he has done and come to faith in him. Those who believe in Jesus Christ are those who have their names written in the book of life. This should lead to great rejoicing (Luke 10:20) since we did nothing to earn our salvation or deserve God’s grace.
1 Now these were the people of the province who came up out of the captivity of those exiles whom Nebuchadnezzar the king of Babylon had carried captive to Babylonia. They returned to Jerusalem and Judah, each to his own town.