There is no shortage of non-believers who blaspheme Holy Scripture by citing its numerous "errors and contradictions". A common complaint concerns the supposed contradictions in the genealogies of Christ presented in the Gospels according the Matthew and Luke.¹
Worse than the incredibly bad logic of atheists, however, is the attempt of some nominally Catholic scholars to impute error to Holy Writ.² This is, of course, against the Church's teachings, who holds the inerrancy of Scripture³ and the historicity of the Gospels⁴.

St. Thomas, in his Commentary on the Gospel of Matthew, points out differences in the genealogies much more clearly than the heretics. Such discrepancies are not only not troubling to the Catholic scholar, they are helpful in understanding the texts. He groups the differences into five categories:

1. 1) Difference in Position: St. Matthew starts out his Gospel with our Lord's genealogy, but St. Luke waits until Ch. 3, after the baptism in the Jordon. As St. Augustine says, this difference is due to the different intentions of the Evangelists. The whole of the Gospel according to Matthew is principally concerned with describing the generation of Christ according to the flesh. Hence it is entitled "the book of the generation of Jesus Christ". Therefore it is fitting that it begins with the genealogy. The Gospel according to Luke, however, is principally concerned with the priestly character of Christ, that is, with Christ's expiation of sins. Therefore, it begins with Zachary performing his priestly functions in the temple. It is fitting, then, that St. Luke place the genealogy after our Lord's baptism, which is the means by which sins are removed.


2. 2) Difference in Order: St. Matthew begins with Abraham and descends down through the generations to Christ. St. Luke, on the other hand, begins with Christ and ascends through Adam to God. This is due to the different purposes of the aforementioned offices of Christ, Son of Man and High Priest. "He who was the Son of God became the Son of man, that man, having been taken into the Word, and receiving the adoption, might become the son of God."⁵ St. Matthew emphasizes the former part of that process, St. Luke the latter. Therefore, it is fitting that St. Matthew proceeds by descent, St. Luke by ascent.


3. 3) Difference in Manner: St. Matthew connects adjoining generations with the verb "begot", while St. Luke uses the phrase "was of". Because the descending generations recorded by Matthew are begotten, Matthew has recorded the physical, carnal ancestors of Christ. The ascending ancestors of Christ recorded by St. Luke, on the other hand, simply belong to subsequent generations. This formulation allows Luke to record legal parents, according to either of two Jewish customs: the brother of a widow without children must marry the widow⁶, so that the legal father (the deceased) may not be the biological father; the parents of a woman without male siblings would sometimes adopt her husband⁷, so that his legal ancestors (the wife's biological ancestors) may not be his biological ancestors.


4. 4) Difference in End: Matthew begins with Abraham and descends down to Christ. Luke starts with Christ and ascends, not only to Abraham, but all the way to Adam and to God. This has to do with their respective audiences: St. Matthew is writing to Hebrews, to whom Abraham is more known than Christ; but St. Luke writes to Greeks, who only know of Abraham by hearing of Christ. And so Matthew introduces Christ to the Hebrews through Abraham, while Luke introduces Abraham and Abraham's God to the Greeks through the man Christ.


5. 5) Difference in Persons Enumerated: St. Thomas has already explained the simple difference in names by distinguishing between legal and biological parents. Here, he points out that Matthew includes women in the genealogy, but Luke does not. Particularly, the women St. Matthew includes are all known sinners: Thamar was a fornicator⁸, Ruth was a idolater (because she was a Gentile)⁹, and Bathseeba was an adulteress¹⁰. This could be to show that Christ descended through sinful man, in the form of a sinner (although without sin), to redeem sinners.

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1. c.f. Forgery in Christianity (about 3/4 of the way down the page), and Bible Perspectives and Christian Contradictions to cite a couple. -WARNING: these sites present blasphemous and ridiculously incorrect readings of Scripture.-
2. For example, Fr. Raymond E. Brown, The Birth of the Messiah (pp. 93-94). -WARNING: Fr. Brown was not an orthodox scripture scholar.-
3. Pope Leo XIII, Providentissimus Deus, 21
4. Vatican Council II, Dei Verbum, 19
5. St. Irenaeus, Adversus Haereses, Bk III, Ch 19:1
6. Deut 25:5-6
7. c.f. 1 Chron 2:34
8. Gen. 38:24
9. c.f. Ruth 1
10. II Kings 11