Matthew 18:12-14
What do you think? If anyone had a hundred sheep, and one of them wandered away, would he not leave the ninety-nine [safe ones] and go to the mountains looking for the one that wandered away?
Luke 15:4
"Which one of you who has a hundred sheep, and loses one of them, would not leave the ninety-nine in a deserted place and go looking for the lost one until he finds it?
John 6:37
Every person [Note: The Greek says, "every thing"] whom the Father gives me will [eventually] come to me [i.e., for salvation]; and I will never turn away that person who comes to me.
John 10:16
I have other sheep [also] which are not [presently] in this corral; I must lead them, too. They will hear my voice and become one flock [i.e., with the others], having one shepherd. [Note: This probably refers to believing Gentiles becoming God's people, along with the Jews].