In the past we thought this was the case because of what is stated at Hebrews 12:16. There it says that Esau did “not appreciate sacred things” and gave to Jacob “his rights as firstborn in exchange for one meal.” So we thought that when Jacob received the “rights as firstborn,” these included the privilege of being an ancestor of the Messiah.​—Matthew 1:2, 16; Luke 3:23, 34.

However, a careful study of other Bible accounts shows that a man did not need to be the firstborn to be an ancestor of the Messiah. Let us consider some of these accounts:

Jacob’s firstborn son was Reuben, by his wife Leah. His first son with Rachel was Joseph. When Reuben committed immorality, he lost his rights as firstborn, and these rights were passed to Joseph. (Genesis 29:31-35; 30:22-25; 35:22-26; 49:22-26; 1 Chronicles 5:1, 2) Still, the Messiah did not come through Reuben or through Joseph. He came through Judah, Jacob and Leah’s fourth son.​—Genesis 49:10.

Luke 3:32 lists five other ancestors of the Messiah, and each one of them seems to have been a firstborn. For example, Boaz was the father of Obed, and Obed was the father of Jesse.​—Ruth 4:17, 20-22; 1 Chronicles 2:10-12.

Jesse’s son David was not a firstborn. He was actually the last of eight sons. However, the Messiah came through David. (1 Samuel 16:10, 11; 17:12; Matthew 1:5, 6) Similarly, the next ancestor of the Messiah was  Solomon, even though he was not David’s firstborn.​—2 Samuel 3:2-5.

This does not mean that being the firstborn son was not important. The firstborn son received privileges that the other sons did not. Often, he became the next head of the household, and he received a double portion of the inheritance.​—Genesis 43:33; Deuteronomy 21:17; Joshua 17:1.

But the rights of the firstborn could be transferred from one son to another. When Abraham sent Ishmael away, his rights as firstborn were transferred to Isaac. (Genesis 21:14-21; 22:2) And as we already discussed, Reuben’s rights as firstborn were transferred to Joseph.

What point, then, was the apostle Paul making at Hebrews 12:16? There we read: “Watch that among you there is no one who is sexually immoral nor anyone who does not appreciate sacred things, like Esau, who gave up his rights as firstborn in exchange for one meal.”

Here, Paul was not discussing the ancestors of the Messiah. Rather, he was giving Christians a warning. He told them: “Keep making straight paths for your feet” so that “no one fails to obtain the undeserved kindness of God.” Sadly, this could happen if they committed sexual immorality. (Hebrews 12:12-16) And in that case, they would be like Esau, who did “not appreciate sacred things” but wanted to satisfy his own desires.

According to the custom of those times, Esau may occasionally have had the privilege of offering sacrifices to Jehovah. (Genesis 8:20, 21; 12:7, 8; Job 1:4, 5) But Esau was so focused on his own desires that he gave away his privileges as firstborn for a bowl of stew. Esau may have wanted to avoid the suffering that Jehovah foretold Abraham’s offspring would experience. (Genesis 15:13) He also showed that he did not value sacred things when he married two pagan women, something that made his parents very sad. (Genesis 26:34, 35) How different he was from Jacob, who made sure that he married a worshipper of the true God!​—Genesis 28:6, 7; 29:10-12, 18.

What do these Bible accounts teach us about the ancestors of the Messiah? Some of them were firstborn sons, and some were not. This was something that the Jews understood and accepted. How do we know this? Because they admitted that the Christ would be a descendant of David, Jesse’s last son.​—Matthew 22:42.