I have gone astray like a lost sheep; seek Your servant, Psalm 119:176
All of us like sheep have gone astray,
Each of us has turned to his own way;
But the Lord has caused the iniquity of us all
To fall on Him. Isaiah 53:6
For the Son of Man has come to save that which was lost.
“What do you think? If any man has a hundred sheep, and one of them has gone astray, does he not leave the ninety-nine on the mountains and go and search for the one that is straying? If it turns out that he finds it, truly I say to you, he rejoices over it more than over the ninety-nine which have not gone astray. Matt. 18:11-13
So... we are all the lost sheep the "ninety-nine" are actually non-existent. The 'ninety-nine' are simply those who have not gotten it yet, that all is grace.