Why are Jesus' family trees different in Matthew and Luke?

Matthew and Luke both trace Jesus' ancestry back to King David, but the names in the middle sections are largely different—which has puzzled readers for a very long time.

One long-standing explanation, going back to an early Christian writer named Julius Africanus, points to a Jewish custom where a man could father a legal heir on behalf of a deceased relative. That could create two genuinely different but both legitimate family lines. Other scholars suggest Matthew traces Joseph's legal line while Luke traces Mary's biological line, since ancient genealogies could be recorded through either parent depending on the purpose.

It's also worth knowing that ancient genealogies weren't always meant to list every single generation. Skipping names to highlight key figures or fit a pattern—Matthew groups his into three sets of fourteen—was an accepted convention, not deception.

No single explanation has become the universally agreed answer, and that's worth saying plainly rather than picking one and presenting it as settled. What both writers agree on is the point they're making: Jesus really did descend from David, as the Old Testament said the promised king would.