The genealogy (Heb. yachas, Gr. genealogia) is listed as such : Genealogy of Jesus Christ is divided into three sets of fourteen generations each, probably to aid memorization.
Matthew gave the names of those who were heirs to the Davidic throne, compared to Luke’s genealogy from Jesus to Adam that records that of the physical descent with his humanity. Both make plain his virgin birth, and therefore his deity.
King David was born approximately 1,030 B.C., became King of Israel in 1,002 B.C., and he died in 962 B.C.. That of course is only 68 years, but in the above mentioned, he is counted as two generations. This only equates to 34 years per generation (or 28 before king and 40 after) and is quite a mystery to me, but it is the response given by most theologians today.
The Exile to Babylon began in 721 B.C. and ended in 586 B.C., Jerusalem fell in 587 B.C. with 70,000 Jews sent into captivity. From King David's time to the Exile covered only 415 years, thus divided by 14 generations would only equal 29.6 years per generation. The Return from Exile occurred in 539 B.C.
From the Exile to Christ only represents 587 years and would only calculate to 41.9 years per generation.
Since Hebrew Scholars believe Abraham to have been in Palestine in 1,900 B.C. around the age of 75, lets make an assumption that this 898 to 973 year range can be divided by 14 also to equate to an average of 64.1 to 69.5 years per generation.
So an overall average of the above would be an assumed two thousand year period divided by (14 x 3 = 42 generations) would equal 42.6 years per generation.
As noted that the 2,160 years of an age can be divided by 42 and equal 51.4 years that I have heard certain Television Evangelist sporting for years. The generation listed here can only be symbolic in its nature. There is more on this subject in Chapter Seven of this book regarding predictions.