“What do sheep symbolize in the Bible?”
The Bible is full of symbols and pictures intended to help us understand the spiritual realities they depict. But as a young man getting serious about studying scripture for the first time, one of the things I had to learn about Bible imagery is that there is rarely a single, consistent interpretation for any figure or picture.
In one sense all of scripture is the product of a single author in the person of the Holy Spirit of God. Because of this, we might expect perfect consistency between image and intended meaning from Genesis to Revelation. But that would be failing to take into account the way inspiration worked.