There are many sources in the Torah and Talmud that stress the importance of lineage.

1. The Talmud in the Tractate Kiddushin (Chapter 4) stresses the importance of yikhus:Ten lineages emigrated from Babylon. The Holy One, Blessed Be He, does not bestow his Divine Presence, other than on Israeli families of noble Yikhus.
2. Yet the Rambam (Mishne Torah, Hilkhot Melakhim, Chapter 12, Halakha 3) gives hope in the future for those who have lost the records of their lineage:In the time of the king Mashiakh, when his kingdom is established and all Yisrael are gathered, their lineage will be revealed by the Holy Spirit which will rest upon him, and he will announce to everyone in Yisrael to which tribe he belongs.

The Torah places importance on yikhus because man is influenced by the qualities and characteristics of his forefathers, both genetically and by the moral values that are passed from generation to generation.

1. The book of Mishlei (Proverbs, 1:8) states:Heed, my son, the moral advice of your father, and do not abandon the teaching of your mother.The Gaon of Vilna comments on this sentence:Man has three partners: the Holy One Blessed Be He, his father and his mother.

1. This theme is taken up in the Talmud (Avot 3:1): Know from whence you came, and where you are going, and to Whom you will have to give account in the future.

1. Only if we know from where we originate in terms of our family heritage will we be in a position to decide what path in life we should take in the future. The late Rabbi Shmuel Gorr, who dedicated his entire life to genealogical research, believed:

Just as we perform many Mitzvot as an act of zeikher le’maaseh bereishit (commemoration of the act of the creation), so the study of our family history can be considered as another aspect of this Mitzvah. When we see ourselves obligated to preserve the continuity of our people’s existence in the world, so will we fulfill our task as it was prescribed by the Holy One Blessed Be He from the time of the creation of Man.

2. The study of genealogy, therefore, can be considered as an act of zeikher le’maaseh bereishit, as we seek to link ourselves, through the generations of our ancestors, with the first living man, Adam. Yet, from the outset, the Biblical commentators explained that illustrious lineage alone was not worthy of note. Commenting on the verses of Bereishit 6:9:These are the generations of Noakh; Noakh begat three sons. Rashi explains: The essence of the history of righteous men is their deeds.

1. One of the most comprehensive collections of genealogical quotations based on Jewish religious sources appears in Rabbi Yosef Zekhariah Stern’s Zekher Leyehosef (1898). The following are some examples:
2. It is worthy of all who seek righteousness to look to the rock from which they were hewn (Yeshayahu, Isaiah 52) and should be Asons of sons are a crown to the elderly, and the glory of sons are their fathers. (Mishlei, Proverbs 17)
3. Like a crown without a kingdom and a gold ring in the nose of one who embraces garbage, so is the value of ancestral Yikhus without personal Yikhus to abandon evil ways. (Yalkut Shimoni; Rashi)
4. If you see a Tzadik who is the son of righteous fathers, he will not hastily sin (Midrash Mishlei 14) But what of the person who is not descended from ancestry worthy of note? Stern answers:It is important to the Almighty that man should abandon the ways of his ancestors (if they were not worthy) and follow the ways of God about whom it is said, “Peace to the distant, who is the seed of distant ones, but came close.”Stern stresses the duty to perpetuate the memory of former generations:

   How can we not stretch out in our hearts to our ancestors who may be forgotten within two or three generations as if they never existed?

5. In our generation, after our ancestors left the countries where their families lived for many generations and emigrated to other countries, we should perpetuate their history. In particular we have a duty to immortalize the memories of the communities and families that perished for the sanctification of the Holy Name during the Holocaust or during anti-Semitic acts throughout the course of Jewish history:To do justice with the deceased and give them a memory upon the face of the earth.
6. The Midrash (Midrash Rabba, Parasha 37) explains the origin of man’s naming system:The early generations that knew their lineage well, gave names to commemorate an event. But we, who do not know well our lineage, give names after our ancestors.
7. The Gaon of Vilna comments on the term used in reference to a deceased person, “May the righteous be remembered for a blessing, and may the name of the wicked decay” (Mishlei, Proverbs 10:7):Remembrance is recalling that which happened in the past, that is, after the death of a righteous person, he is not just a memory, but he is a blessing. But as for the wicked, even his name is contemptible.
8. Throughout Jewish prayer the concept of recalling our ancestors is a recurrent theme. The central prayer of the three daily services, the Shmonah Esreh, begins with:God of Avraham, God of Yitskhak, God of Yaakov…remember the good deeds of our fathers and bring the redeemer to their sons’ sons.
9. Amongst the most important statutes given to the People of Israel, the Ten Commandments, is the commandment: Honour your father and your mother…. In the High Holy Day liturgy the relationship between God and man is couched in familial terms:If you regard us as sons, have pity upon us like a father. Our Father, our King….
10. The tracing of family history is a most effective way to appreciate Jewish history on a personal level. As we recite in the Hagaddah of the Pesakh (Passover) festival:In each generation man must regard himself as if he himself came out of Egypt, as it is said and you should relate it to your son on that day, saying… People make history by their reaction to the demands and opportunities of their environment. An awareness of personal family history establishes a link in the chain of Jewish existence.

Jews left Babylon and Eretz Yisrael and spread out through the Diaspora. Many of their genealogical records were lost. Yet certain families painstakingly preserved their traditions of descent. The scholarly family of the Kalonymides, which believed in its Davidic descent, left Babylon about the eighth century, settled in Italy, and then moved to the Rhineland and France in the ninth and tenth centuries. From this family emanated the great Biblical and Talmudic commentator Rashi (1040-1105). Rashi’s family and disciples established centers of learning in many towns in Western Europe and later, in the fourteenth century, in Eastern Europe. Thus a vast interrelated dynasty of rabbinic families spread across Europe, establishing a framework for future genealogical research.