In Luke, Nathan son of David is an ancestor of Jesus.
In Matthew, Solomon son of David is an ancestor of Jesus.
So which applies?
The short answer for this discrepancy, is that Luke covers Mary's genealogy.
- In Luke's genealogy, Heli, listed as the father of Joseph, actually had 2 daughters: The first is Mary, and the other was Zebedee’s unnamed wife (Matthew 27:56; John 19:25).
- Back then, when there were no sons to preserve the inheritance in accordance with the Law of Moses (Numbers 27:1–11; Numbers 36:1–12), the husband would become the son upon marriage to keep up the family name.
- Therefore, Joseph, when he married Mary, became the "son of Heli" according to the Law of Moses and could legally be included in the genealogy.
It is also worth noting that in Genesis, God said "between your seeds and her (the woman's) seed, he will crush your head and you will strike his heel" - extrapolated, we have a link to the seed of a woman (Mary).
