Albert Barnes Commentary Mark 6:34

"And he came forth and saw a great multitude, and he had compassion on them, because they were as sheep not having a shepherd: and he began to teach them many things." — Mark 6:34 (ASV)

Many people—as sheep, etc. They had no one to teach them and guide them. The priests and scribes were proud, corrupt, and despised the common people and neglected them.