The "Benjamin of the Family" is an idiomatic expression referring to the youngest son in the family. In modern usage, "Benjamin of the Family" may also be used to refer to female children as well. The expression, like the name Benjamin, has its origins in the biblical tale of Jacob. "Benjamin of the family" is a common saying in cultures that have been influenced by the Christian, Muslim, and Jewish religions.
Benjamin is a biblical name, and is therefore common among the Abrahamic religions. While the name Benjamin has a religious origin, it is not used exclusively by religious individuals and remains a popular name in secular families. In addition to its use as a given name, Benjamin is also a common surname.
The Book of Genesis tells the story of Jacob and Esau, two brothers who fought for their Father's inheritance. Jacob, the younger and weaker brother, used wit and cunning to trick first his brother and then his father into surrendering what would ordinarily have gone to his older brother Esau. Later in life, Jacob was a wealthy man with many flocks and tents as well as a large family. He has twelve sons and names the youngest one Benjamin, which means "right hand son" in Hebrew. Some believe that this means that Benjamin was Jacob's favorite son, or at least that Jacob thought so when Benjamin was born.
Muslim accounts of Benjamin's life also say that he was a compassionate son and was the only son to stay by his father's side in the most difficult times. This may be because of their shared status as youngest brothers, or because he was simply a very righteous. This behavior may also contribute to the belief that Benjamin was Jacob's favorite son.
Although Benjamin was the youngest child in his family, he was also very important. During his lifetime, Benjamin traveled from the land of Canaan to Egypt, and eventually founded the Israelite tribe of Benjamin. Many years later when the Tribes of Israel chose to have a king, that king was selected from the Tribe of Benjamin, although that was the least populous tribe at the time.
The idiom "the Benjamin of the family" is a reference to these biblical tales about younger brothers and small tribes. It does not hold a negative connotation. Benjamin, like his father before him and his descendants to follow, was younger and weaker than his brothers but also important and accomplished many things.