Why does the shepherd in the parable of Luke 15 focus on the one lost sheep out of the hundred?
The shepherd focuses on the one lost sheep because that sheep knew it was lost and in trouble, while the ninety-nine, though also lost without a shepherd, did not know it. The distinction is awareness of being lost, not merely being lost.
Les explains that in the parable of Luke 15, the shepherd concerns himself with the one sheep out of a hundred because that little fellow knew he was lost. The ninety-nine went out roaming in the desert or wilderness without a shepherd, and sheep without a shepherd are lost, but they did not know it. The lost lamb knew he was in trouble and was bleeding his head off, while the rest roamed around lost and never knew it. Les then connects this to separation: God lost the human race.