Shelah’s father was Arpachshad
Arpachshad became the father of Shelah; and Shelah became the father of Eber.
Genesis 10:24 NASB
12 Arpachshad lived thirty-five years, and became the father of Shelah; 13 and Arpachshad lived four hundred and three years after he became the father of Shelah, and he had other sons and daughters.
Genesis 11:12-13 NASB
Shelah’s father was Cainan
23 When He began His ministry, Jesus Himself was about thirty years of age, being, as was supposed, the son of Joseph, the son of Eli, 24 the son of Matthat, the son of Levi, the son of Melchi, … 35 the son of Serug, the son of Reu, the son of Peleg, the son of Heber, the son of Shelah, 36 the son of Cainan, the son of Arphachshad, the son of Shem, the son of Noah, … 38 the son of Enosh, the son of Seth, the son of Adam, the son of God.
Luke 3:23-24, 35-36, 38 NASB
The Problem
The book of Genesis states that Arpachshad and Shelah are father and son. However the Gospel of Luke implies that Shelah was a son of a certain Cainan and this Cainan was a son of Arpachshad. So in Luke Shelah is described as a grandson and not a son of Arpachsad. And of course this is food for Bible critics.
Joseph lineage?
To solve this problem we need to question the accuracy of the translation of Luke 3:23-24. This translation is old and reflects the view that the genealogy of Joseph is given by Luke. Despite scholarly support for this view it doesn’t seem to make much sense. Would Luke give the names of 77of Joseph’s forefathers after implying that Joseph was not the father of Jesus and that only the people thought so? Not very convincing, is it? Furthermore, according to Matthew (1:16) the father of Joseph was a certain Jacob and not Eli (Luke 3:23).
Mary’s lineage
And so for good reason many eminent theologians have rejected Joseph’s lineage as recorded here by Luke. A few names may be given: Luther, Bengel, Lightfoot, Wieseler, Codet, Weiss, Robertson, Greijdanus, Geldenhuys, (J.) Wenham, McDowell. They have instead proposed that the lineage given by Luke relates to Mary.
Better translation
As the translation influences the solution of the problem, we will make some adjustments.
1. In Luke 3:23b we take a word-for-word-translation for the beginning of Luke’s list, from “being …” etc.
2. We follow the Byzantine text (Majority text): ‘son’ preceding Joseph, instead after ‘being’. This is the most natural text variation (no separation of ‘son’ and ‘Joseph’).
3. Punctuation marks are not in the Greek text and are mostly clear. In exceptional cases as here they depend on a chosen interpretation (see above).
[NASB 23 When He began His ministry, Jesus Himself was about thirty years of age,] being – as was supposed (the) son of Joseph – the son of Eli, the son of Matthat, the son of Levi, the son of Melchi,… 35 the son of Serug, the son of Reu, the son of Peleg, the son of Heber, the son of Shela, 36 the son of Cainan, the son of Arphachshad, the son of Shem, the son of Noah, …
Results
In the new translation we have got a subordinate clause “as was supposed (the) son of Joseph” (an interjection, or parenthesis), with the result that there is another relation of sonship: between Jesus and Eli. Jesus is the son of Eli; so there is no other possibility than that Eli is the father of Mary and Jesus is the grandson of Eli according to the rule: the son of a son is a son.
As Jesus is the grandson of Eli it is clear that the other names after Eli refer to Eli’s ancestors, and not necessarily to his biological sons. In the same way there is not necessarily a biological sonship between Shelah and Cainan expressed in Luke 3:36.
Solution to the proposed contradiction
Shelah is not the biological son of Cainan as suggested in the old translation of Luke 3:36, which seem to contradict the Genesis information saying that Shelah was a biological son of Arpachsad.
How is it possible that Shelah is a son of Cainan (Luke 3:36) and a son of Arpachshad (Genesis 10:24, 11:12-13)? There is only one possibility: Cainan died shortly after his marriage (maybe an accident), when he was about 17 years. His father Arpachshad married his widow and begot a child (Shelah) for Cainan at the age of 35. So Arpachshad's first marriage also had been pretty early at the age of about 17. We read about another example in Genesis 38:26-28 of what would be called later a levirate marriage: Judah became the father of Perez and Zerah, the sons of his daughter-in-law (Genesis 38:26-28).
No Bible Contradiction
Additional remarks
– Luke’s list extends back from David to Abraham and from Abraham to Adam and God. This latter group represent the great spiritual figures who lived before Abraham. They saw the coming of the Messiah in the future and so Jesus is also a son of Peleg, of Heber, of Shelah etc.
– Luke’s list is primarily to be understood spiritually and then genealogically. This is certainly what Luke had in mind: to present Jesus as the long expected Messiah of world history.
– Information about Cainan could have been borrowed by Luke from the Psalms that were current in the temple music of his time. They formed a distinguished body of ancient texts alongside the canonical book of Psalms of the Old Testament (Luke 24:44). In the same way Jude could write about Enoch in the letter of Jude (vs. 9).