This question poses two problems.
- What is a Jew?
- Where did the Jews come from?
The second question is the easier one to answer.
Since all human beings came from one pair of human beings, namely Adam and Eve, then all the various races on earth are simply branches of that tree. This fact is no longer theory. Since the inception of Genetics, scientists have proven the human race stems from a single pair of people.
If all races on earth are the branches of one tree, then Jews must be one of those many branches. This would be true if the Jewish people stemmed from a single source sometime after Adam and Eve; but they don’t.
The nation that Jews come from is named Israel. It was unique 4,000 years ago. It was different than any other nation, or race, on earth. The difference was within the people of the nation of Israel. The people were not born from one pair of human beings, which would be the essence of a tribe or nation; but vary widely.
The beginning of Israel was spawned from many of the races of earth. Each individual race has an outward appearance that can be traced back to an origin, which identifies the race as being the same nation or family of people. It is similar to tigers and lions. While both animals are huge cats, they differ in their coloring, size, and shape. We don’t have to search to see this principle work.
If you go to China, you will find a similar appearance amongst all the people. Therefore, Chinese people are easily identified by their physical appearance; which appearance separates them from Australian Aborigines, European Whites, or the African Negro. It is the outward physical appearance of a race that serves to identify it and make it a separate branch of human beings. Yet, the Chinese, or European, or African, although quite different in outward appearance, are simply different branches, or families, that stemmed from the same two parents known as Adam and Eve!
The first pair of human beings on earth, Adam and Eve, is the root system of the entire human family tree that exists today. While the Jewish people do not have the same distinguishing mark, or a particular outward facial appearance, neither do they have a similar body structure. The reason the Jewish people do not have a particular appearance is: the nation of Israel began with defectors who left their original tribes and nations because they rejected the false religious tenets of their nations. Hence, Israel was populated by people from many nations and became a unique branch of the human tree.
This does not mean that Jews are aliens from outer space. They did not come to earth from another planet. It simply means that all Jewish people are descendants of Adam and Eve like every other races of human beings on this planet, but they are not descendants of each other, as in other races.
It would be like a family that was childless. Although there are ten children in the family, they were not born by the mother and father of their family, since they were adopted. The Jews are a conglomeration of other races that have joined themselves together to become one nation.
The common denominator in the nation of Israel was, and is, their belief in One God. The God of Creation! Therefore, Israel is not a branch of the original tree, but a mixture of all the branches of the original tree, because Israel has pieces taken from all the various branches.
This is what makes the Jewish Nation unique. They were not born into their nation like the other races, but were grafted together by God to produce a unique independent tree that would give birth to a unique people God could use to teach the other branches about Him.
Somewhere in the history of every Jewish family, the original father of that family came from one of the many Gentile branches of the human tree; and that particular father decided to become a Jew. So while his children, and their children, are born into the nation, just like in other nations, the various families of Israel do not carry one outward identifying appearance or mark, which distinguishes them as all other races were distinguished on the planet earth until recently.