Lions are nocturnal creatures, and are a symbol of authority and command over subconscious thought(as night is an ancient symbol of the subconscious - or dream states). The lion is considered by many ancient cultures to be a solar animal judgment.
Proverbs "A righteous man regardeth the life of his beast: but the tender mercies of the wicked are cruel." Cruelty to animals is judged by God. Any Friend of God is a friend to all creatures great and small.