'Lost Sheep' in the Bible

I have gone astray like a lost sheep. Seek your servant, for I do not forget your commandments.

My people have been lost sheep: their shepherds have caused them to go astray; they have turned them away on the mountains; they have gone from mountain to hill; they have forgotten their resting place.

Rather, go to the lost sheep of the house of Israel.

But he answered, "I was not sent to anyone but the lost sheep of the house of Israel."