Why is the ninth month called September?
c.1300, from Anglo-French heir, Old French oir "heir, successor," from Latin heredem (nominative heres) "heir, heiress" (see heredity). Heir apparent (late 14c.) has the French order of noun-adjective, though it was not originally so written in English. It is the heir of one still alive whose right is clear. After death the heir apparent becomes the heir-at-law.
Under the patriarchs the property of a father was divided among the sons of his legitimate wives (Gen. 21:10; 24:36; 25:5), the eldest son getting a larger portion than the rest. The Mosaic law made specific regulations regarding the transmission of real property, which are given in detail in Deut. 21:17; Num. 27:8; 36:6; 27:9-11. Succession to property was a matter of right and not of favour. Christ is the "heir of all things" (Heb. 1:2; Col. 1:15). Believers are heirs of the "promise," "of righteousness," "of the kingdom," "of the world," "of God," "joint heirs" with Christ (Gal 3:29; Heb. 6:17; 11:7; James 2:5; Rom. 4:13; 8:17).