The Gospel accounts of Matthew and Luke delineated the lineage of Jesus Christ, establishing that He is the Son of David, the Messiah, the Savior of the World.
The two genealogies differ from David up to Joseph, the earthly father of Jesus.
Scholars, readers, pastors have advanced a number of explanations, all of which glorify Jesus.
Matthew was writing his account to the Jews so that they would know and believe that Jesus Christ is the Messiah. He began with Abraham, connecting Jesus to the Patriarchs, then Matthew listed the Kings of Israel, followed by the leaders and private citizens of the Israelite captivity when they returned from Babylon and later Persia.
Matthew's account focuses on Christ the King, the King of Kings and the Lord of Lords.
Luke's account was precisely for a Gentile audience, an account which mentions the unclean "ravens" in the Sermon on the Mount, while Matthew's account left out that reference. Luke's account presents Gentiles in a more prominent light, including the Centurion with great faith. Luke's account takes into account the common man, including the thief who asked Jesus to remember him when He entered into His Kingdom.
The genealogy in Luke's account diverges from David on down, referencing Nathan, who was David's third son by Bathsheba, who was the wife of Uriah the Hittite. Luke's account is more exhaustive, connecting Jesus the son of Joseph, the son of David, all the way to Adam, proving that Jesus is the Savior of the whole world, not just of the Jews.
The Lucan genealogy honors the line according to Mary, who was of humble birth, yet also a descendant of David. The LORD had prophesied:
"Thus saith the
LORD, Write ye this man childless, a man that shall not prosper in his
days: for no man of his seed shall prosper, sitting upon the throne of David,
and ruling any more in Judah." (Jeremiahs 22: 30)
The LORD cursed the wicked King Jeconiah, yet this king does appear in the lineage of Matthew's Gospel, once again promoting the grace of God which triumphs over the sin of men.
Yet the LORD honored this curse in that the lineage of His Beloved Son also descended through another line.
The new revelation explaining this difference touches on the humble origins of Mary, not just her distinction from the royal line. Jesus is the savior of the world, not just elites or "noble persons" by the world's standards. I believe that another reason why Luke's genealogy diverges from David through Nathan instead of Solomon is that Luke wanted to present another truth about Jesus: that he was of humble origins as well as divine and royal stature. Jesus is not merely an imperious, untouchable monarch, but He is also the Son of Man who understands all that we endure.
Because of Luke's emphasis on Jesus as "Son of Man", Jesus is also our high priest:
"For we have not an high priest which cannot
be touched with the feeling of our infirmities; but was in all points tempted
like as we are, yet without sin." (Hebrews 4: 15)
The connection of "Son of Man" and "High Priest" is supported further since Luke references Zechariah the High Priest, who received the prophecy from the archangel Gabriel about a son, John.
Another beautiful revelation about Jesus emerges in this divergence of genealogies. David had these two sons with Bathsheba, whose presence in Matthew's lineage right away glorifies God, whose grace is greater than man's sin, as Bathsheba had committed adultery with David, who then had her lawful husband Uriah killed on the field of battle.
The two sons are Nathan, which means "Giver" and "Solomon", which means "Peace".
God the Father wants us to see His Son as "Giver":
"What shall we then
say to these things? If God be for us, who can be against us?
"He that spared not
his own Son, but delivered him up for us all, how shall he not with him also
freely give us all things?" (Romans 8: 31-32)
And also, Paul writes:
"And by their
prayer for you, which long after you for the exceeding grace of God in you.
"Thanks
be unto God for his unspeakable gift." (2 Corinthians 9: 14-15)
"Grace" is the gift unspeakable which Paul mentions, yet Jesus is "Grace", God's unmerited favor personified in our lives, too.
"For the law was given
by Moses, but grace and truth came by Jesus Christ." (John 1: 17)
God the Father also wants us to see His Son as "Peace":
"Therefore being justified by faith, we have peace with God through our Lord
Jesus Christ:" (Romans 5: 1)
Paul also writes:
"For he is our
peace, who hath made both one, and hath broken down the middle wall of partition
between us." (Ephesians 2: 14)
Jesus is Grace, God's Gift to the world, and He is our peace, and the two genealogies establish this wonderful picture for us, members of His Body.