Most readers of Matthew’s gospel, I suppose, skip the first chapter entirely. After all, it is only a boring genealogy. But at least look at the first six verses. Genealogies in the Bible do not often mention a man’s mother, but Matthew took time to identify four mothers, and each mother reminds us of a particular sin.
The disgusting story of Judah and Tamar, told in Genesis 38, reads like the story line of the edgiest of soap operas. God took the life of Tamar’s husband, Judah’s oldest son Er, for unspecified wickedness. It then became the responsibility of the second son, Onan, to provide his brother with an heir by having sex with his widow. He did not want to, but instead of refusing outright, he repeatedly withdrew from Tamar so that his semen fell on the ground. Finally, God killed him, too. Judah withheld his youngest son Shelah. He told Tamar he was too young, but secretly feared that he would meet the same fate.
Years later, Judah’s wife died. Tamar, living out her widowhood at her father’s house, realized Judah never intended to give her to Shelah, but she was still determined to have children. Legally, it could only happen through Judah’s family, so she disguised herself as a shrine prostitute, seduced Judah, and bore him twins.
Rahab was a prostitute in Jericho. When Joshua sent two spies to Jericho, Rahab hid them and helped get them out of town safely. As a reward, they promised her protection. After the fall of Jericho, she married Salmon. While that story is certainly not so disgusting as the story of Tamar, Moses had strictly forbidden Hebrew men from marrying Canaanite women, saying they would be a snare and a temptation to the entire society. New Testament authors praise Rahab, but Salmon had no business marrying her, for Moses also declared that no one born of a forbidden marriage could ever join God’s assembly, nor could his descendants down to ten generations.
Forbidden marriages included Moabites, Ruth, for example. In this well-known story, Naomi, along with her husband and two sons, went to Moab to escape a famine. The Bible records nothing of the three men besides their names, but both sons took Moabite wives, and Naomi does not appear to have been an especially godly woman.
The two sons died without heir, and Naomi returned home to Bethlehem with Ruth. There, Ruth met Boaz and found favor in his eyes because of her devotion to Naomi. To shorten the story, they married, even though Moses had forbade marrying Moabites. Boaz was a godly man, even regarded by at least one commentator as a Christ figure, but as Salmon and Rahab’s son, and therefore son of a forbidden marriage himself, legally he should not have been regarded as part of the assembly of the Israelites. For that matter, since the prohibition lasted past ten generations, David himself was likewise ineligible. There are some powerful lessons about grace here that I will write about later.
Matthew does not even name the fourth woman, who had been Uriah’s wife. I suppose David’s inexcusable dalliance with Bathsheba is familiar enough that I don’t have to say anything more about it. Four women, four stories of sin, Most of us today would not criticize Salmon for marrying Rahab or Boaz for marrying Ruth, but Judah’s relationship with Tamar and David’s with Bathsehba would probably be regarded as totally immoral in any society at any time in history.
Since all have sinned, surely everyone else Matthew mentions in his genealogy could have provided similar stories, although not necessarily involving sexual relations. Jesus could redeem the world only being both fully human and fully God. How could this combination possibly happen without a fatal contamination on the human side by sin? How could sinless God unite himself with sinful humanity to redeem the world?
The only correct answer to the second question it that even omnipotent God cannot accomplish that. God’s omnipotence means that he can do anything that can be accomplished by power. Power cannot accomplish uniting his sinlessness with sin without polluting the sinlessness. So God used his power to create a sinless humanity by means of the virgin birth.
Explanations of the virgin birth I have heard all seem to imply that somehow sex would introduce sin and that the man’s semen would have to be removed from the equation. That is correct as far as it goes, but there always seems to be the tacit assumption that any birth requires a woman’t egg cell. The Catholics even have a doctrine of the immaculate conception to make Mary sinless. That tacit assumption is incorrect, which makes the doctrine of immaculate conception quite unnecessary.
Jesus later said that anyone who does not enter the sheepfold by the door is a thief. The legitimate door into this world as a human is through a mother’s womb. The normal conception consists of the union of sperm and egg implanted in the uterus, where it grows and develops until the time of birth. Jesus’ supernatural conception consisted of the creation of a special embryo, not owing anything to either human parent, implanted in the uterus.
God could unite his Spirit with this newly created human embryo. The supernatural conception, proceeding in an entirely natural pregnancy and birth guarantees a legitimate human being. God did not require a virgin birth because sex (which, after all he invented and ordained) is somehow immoral. He required it as evidence that Jesus’ conception was as supernatural as his birth, life and death as a human were natural.
The Spirit of God united himself to this newly created sinless humanity without polluting himself. That is how Jesus became both fully God and fully human. From that unity, God’s power could and did accomplish his redemptive purpose.