One example of an inspirational quote that may be used for a sister's birthday message is, "Help one another, is part of the religion of sisterhood," by Louisa May Alcott. Another example is, "Sister is probably the most-competitive relationship within the family, but once the sisters are grown, it becomes the strongest relationship," by Margaret Mead.
Louisa May Alcott was the American author who wrote the literary classic "Little Women." She also published poems and short stories under the pen name A.M. Barnard. Louisa studied with family friends such as Ralph Waldo Emerson, Henry David Thoreau and Theodore Parker. The quote from her about sisterhood may be used in a birthday message to thank a sister for being supportive or to remind a sister that support is available.
Margaret Mead was an American anthropologist and activist for women's rights. She is well-known for her lectures that tackled controversial topics and writing columns for "Redbook" magazine. She also published an autobiography titled "Blackberry Winter." Her quote about sisterhood describes how sisters are known to fight with each other in youth, but often grow up to be best friends. This quote may be used to remind a sister of the funny times they had as competitive children and to show appreciation for the friendship that was built.