Jacob was the thirteenth generation from Noah. When Noah’s eldest son died Jacob was 50 years old.
The combined ages of seven patriarchs equal a sum five hundred years greater than the time that has elapsed from the creation of the world to the present time.
2.
“Every one that findeth me shall slay me” (Gen. iv, 14).
“And the Lord set a mark upon Cain, lest any finding him should kill him” (15).
“And Cain went out from the presence of the Lord, and dwelt in the land of Nod” (16).
“And Cain knew his wife: and she conceived, and bare Enoch; and he [Cain] builded a city” (17).
Cain, believing that he had a plurality of lives, and fearing that every one who found him would take one, appealed to God, who set a mark on him so that his father and mother, the only persons in existence besides himself, would know him. Then going out from the presence of Omnipresence, he went to a country where nobody lived, married a wife, and built a city with a population of three inhabitants.