'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 become lost sheep;Their shepherds have led them astray.They have made them turn aside on the mountains;They have gone along from mountain to hillAnd have forgotten their resting place.

but rather go to the lost sheep of the house of Israel.

But He answered and said, “I was sent only to the lost sheep of the house of Israel.”