Answer: A lamb is seen as an animal of innocence. When you think of a lamb you think of a sweet, soft, kind, and loving animal instead of a bear or tiger. This innocence is associated with the stereotype that the lamb is sweet and kind. " Softest clothing, woolly, bright; Gave thee such a tender voice, Making all the vales rejoice?", explains how the lamb is seen as innocent.
Because a lamb is seen as being innocent. For example would you prefer a lamb or a wolf. When you think of a lamb you think of soft, white, fluffy, cute animal that could do no harm. Innocents.