Dogs are known to be "a man's best friend".
This saying has always been proven to be true since dogs have always been at the human's side since ancient times.
Their loyalty does not end with them being at the side of humans, it extends to the dogs obeying the command of their human - owner.
They even obey the order of their human - owner even if their life is at stake.
This loyalty trait of dogs just proves that they are indeed man's best friend.