'Ninety nine' in the Bible

What do you think? If a man has a hundred sheep, and one of them has gone astray, does he not leave the ninety-nine and go to the mountains in search of the one that went astray?

And if he finds it, truly, I say to you, he rejoices more over that sheep than over the ninety-nine that did not go astray.

"What man of you, having a hundred sheep, if he loses one of them, does not leave the ninety-nine in the wilderness, and go after the one which is lost until he finds it?

I tell you that in the same way there will be more joy in heaven over one sinner who repents than over ninety-nine righteous persons who need no repentance.