1. Physiological Heredity:
Heredity, in modern language, is the law by which living beings tend to repeat their characteristics, physiological and psychical, in their offspring, a law familiar in some form to even the most uncultured peoples. The references to it in the Bible are of various kinds.
2. Hebrew Conception of Heredity:
The question, however, is considerably complicated by the intense solidarity that the Hebrews ascribed to the family. The individual was felt to be only a link in the chain, his "personality" (very vaguely conceived) somehow continuing that of his ancestors and being continued in that of his descendants. After death the happiness (or even existence; see Death) of this shade in the other world depended on the preservation of a posterity in this. Hence, slaying the sons of a dead man was thought to affect him directly, and it would be a great mistake to suppose that an act such as that of 2Sa 21:1-9, etc., was simply to prevent a blood-feud. Nor was it at all in point that the children might repeat the qualities of the father, however much this may have been realized in other connections. Consequently, it is impossible to tell in many cases just how much of a modern heredity idea is present.
The most important example is the conception of the position of the nations. These are traced back to single ancestors, and in various cases the qualities of the nation are explained by those of the ancestor (Ge 9:22-27; 21:20,21; 49, etc.). The influences that determine national characteristics are evidently thought to be hereditary, and yet not all of them are hereditary in our sense; e.g. in Ge 27, the condition of the descendants of Jacob and Esau is conceived to have been fixed by the nature of the blessings (mistakenly) pronounced by Isaac. On the other hand, Ezra (9:11,12) thinks of the danger of intermarrying with the children of a degenerate people in an entirely modern style, but in De 23:3-6 the case is not so clear. There a curse pronounced on the nations for their active hostility is more in point than moral degeneracy (however much this may be spoken of elsewhere, Nu 25:1-3, etc.), and it is on account of the curse that the taint takes ten generations to work itself out, while, in the case of Edomite or Egyptian blood, purity was attained in three. Hence, it is hard to tell just how Ex 20:5,6 was interpreted. The modern conception of the effect of heredity was surely present in part, but there must have been also ideas of the extension of the curse-bearing individuality that we should find hard to understand.
3. Abraham’s Children:
The chiefest question is that of the Israelites. Primarily they are viewed as the descendants of Abraham, blessed because he was blessed (Ge 22:15-18, etc.). This was taken by many with the utmost literalness, and physical descent from Abraham was thought to be sufficient (especially Mt 3:9; Joh 8:31-44; Ro 9:6-13), or at least necessary (especially Ezr 2:59; 9:2; Ne 7:61), for salvation. Occasionally this descent is stated to give superior qualities in other regards (Es 6:13). But a distinction between natural inheritance of Abraham’s qualities and the blessing bestowed by God’s unbounded favor and decree on his descendants must have been thoroughly recognized, otherwise the practice of proselytizing would have been impossible.
4. Heredity and the New Testament:
In the New Testament the doctrine of original sin, held already by a certain school among the Jews (2 Esdras 7:48), alone raises much question regarding heredity (compare 1Co 7:14). Otherwise the Old Testament concepts are simply reversed: where likeness of nature appears, there is (spiritual) descent (Ro 4:12; Ga 3:7, etc.). None the less, that the Israel "after the flesh" has a real spiritual privilege is stated explicitly (Ro 3:1,2; 11:26; Re 11:13).
See Blessing; Curse; FAMILY; SALVATION; SIN; TRADITION.