Genesis 4:17-24

After moving to the land of Nod, possibly in an attempt to return to the Garden of Eden, we see Cain now unable to re-enter Eden. Therefore, he must find a way to move forward in his new reality. This is a reality where the ground does not yield its strength (v. 12), resulting in him living as "a fugitive and a vagabond" (v. 12).

First Wife, First Grandchild, First City

Verse 17 introduces a series of firsts. Although Cain's wife is not the first woman or wife in the most literal sense, as Eve holds that position, she is the first woman to be a wife in the more traditional sense of growing up, falling in love, and getting married. The text provides very little information about her, sparking countless questions. Apart from various traditions and speculations, we cannot definitively answer the question of who Cain married. If we assume, as I do, that Adam and Eve were the starting point of the human population, and that Cain married a human, we are left to conclude that Cain likely married a close or, given enough time, a more distant family member.

The record of Seth's birth when Adam was 130 years old (Gen. 5:3) gives us some important context. Cain and Abel were adults by the time Seth was even born, suggesting that other children were likely born to both brothers. If we assume that Cain and Abel were born in the Garden of Eden, or even shortly thereafter, and that Seth was born five years after Abel's death, then Cain and Abel had 100 years to have children, as did Adam and Eve. Mathematically, the population could have grown to over 2 million people by the time Adam was 130 years old. Whatever the scenario, verse 17 presumes the existence of a sizable population, and we must assume a natural progression for this to have occurred (see Appendix 20, The Companion Bible).

It is crucial to understand the mathematical possibilities of such early human demographics. Considering Adam and Eve as the progenitors, let us construct a model of population growth under specified conditions to gain further insight into the potential size of the population around the time of Cain and Abel.

Assuming that Adam and Eve began their family soon after Eve’s was formed by God, and based on the genealogies and lifespans presented in Genesis, we might hypothesize a scenario where:

Each couple begins childbearing at the age of 30.
They have one child every 18 months.
The childbearing period extends for 100 years.
Each child survives to reproduce under similar conditions.

To visualize the implications of these assumptions, consider the following detailed calculations:

Each couple produces approximately $\frac{100 \text{ years}}{1.5 \text{ years/child}} = 66.67$ children.
Starting with just one couple, the next generation would ideally begin 30 years later, giving each successive generation the same reproductive pattern.

Implementing this into a model where each generation fully reproduces under these conditions, the growth is calculated as follows:

The first generation, starting 30 years after creation, would comprise about 33 couples, given the practicality of pairing.
By the end of 60 years, these 33 couples would contribute approximately 1,122 couples.
After 90 years, this second generation would expand to around 38,148 couples.
By 120 years, a significant increase would result in about 1,297,032 couples.