Did Jesus Have Biological Siblings?
According to John 3:16, Jesus is God’s only begotten Son. Joseph was never Jesus’ biological father, therefore Jesus never had full siblings. However, those who argue that Jesus had half-siblings, would have to prove that Mary had other biological children, to which some reference the following verse:
“Is not this the carpenter's son? Is not his mother called Mary? And are not his brothers James and Joseph and Simon and Judas?” — Matthew 13:55
Yet, in the wider biblical and historical context, the so-called brothers of Jesus mentioned in the Gospels are not the sons of Mary, neither are they the sons of Joseph from a previous marriage. Instead, they were actually cousins of Jesus...
The Etymology Of The Greek Word ‘Adelphos’
On both occasions, the Gospel writers used the word ‘adelphos’ meaning brother in a literal sense (Matthew 13:55, Mark 6:3). However, in the Septuagint, the Greek translation of the Hebrew Bible, and the New Testament, the word ‘adelphos’ when used does not always refer to a biological brother.
Genesis 14:14 - Lot is described as Abraham’s ‘brother’ despite being Abraham’s nephew.
Genesis 29:15 - Laban referred to Jacob as his ‘brother’ even though Jacob was his nephew.
1 Chronicles 23:22 - The sons of Kish, referred to as the ‘brethren’ of the daughters of Eleazar were actually their cousins.
Matthew 23:8 - Jesus called His disciples ‘brothers.’
Acts 9:17 - Ananias called Saul his ‘brother.’
As the word ‘adelphos’ is vague, we cannot assume that the brothers of the Lord mentioned in the Gospels were biological brothers of Jesus or other children of Mary. To assume this, would be an example of eisegesis, where one reads into Scripture something that is simply not there.
Biblical Identification Of Jesus’ Brothers:
Matthew and Mark identify that James and Joseph were not biological brothers of Jesus. They were children of the Other Mary and not the Virgin Mary.
When we compare this to John's Gospel, we know for certain that the "brothers" of Jesus were not sons of Joseph from a previous marriage either. Instead, their mother Mary was married to Clopas.
“Meanwhile, standing near the cross of Jesus were his mother, and his mother's sister, Mary the wife of Clopas, and Mary Magdalene.” — John 19:25
If Mary, the wife of Clopas was the sister of Jesus’ mother, then James and Joseph were cousins of Jesus.
“Then after three years I did go up to Jerusalem to visit Cephas and stayed with him fifteen days; but I did not see any other apostle except James the Lord's brother.” — Galatians 1:18-19
There were only two apostles named James. We know that Paul cannot be referring to James, the son of Zebedee, as he was martyred early on (Acts 12:2). Therefore, Paul must be referring to the other James, the son of Alphaeus (Luke 6:15).
However, we have already identified that this James, was the son of the other Mary and Clopas. Thus, scholars conclude that Alphaeus and Clopas are the same person. Nevertheless, Scripture confirms that James the "brother" of the Lord was not a biological brother of Jesus.
“Jude, a servant of Jesus Christ and brother of James,” — Jude 1:1
The third so-called "brother" of the Lord identifies himself as the brother of James and not Jesus. Therefore Jude, together with James and Joseph, were cousins of Jesus.
Historical Identification Of Jesus’ Brothers:
The testimony of the 2nd-century historian Hegesippus recorded by Eusebius in the 4th century confirms that the “brothers” of the Lord were Jesus' cousins and were influential Early Christians.
“The same writer [Hegesippus] also [writes]…as follows: “After James the Just had suffered martyrdom for the same reason as the Lord, Simon, his cousin, the son of Clopas, was appointed bishop, whom they all proposed because he was another cousin of the Lord." - (Hegesippus, quoted in Eusebius, Church History, 4.22)
Simon, the fourth so-called “brother” of Jesus succeeded James, as the Second Bishop of Jerusalem. As another son of Clopas, Simon was also Jesus’ cousin.
“For Hegesippus records that Clopas was a brother of Joseph.” - (Hegesippus, quoted in Eusebius, Church History 3.11.2)
Though Scripture states that the Virgin Mary and Mary, the wife of Clopas, were sisters (John 19:25) it is unlikely that both sisters would have been named Mary. As Hegesippus clears up, Clopas and Joseph were brothers, thus their wives were related as sisters-in-law. As with 'adelphos,’ here the word ‘adelphe' meaning sister was also used in a loose sense. Thus, the claim that the "brothers" of the Lord were cousins of Jesus is both consistent with Scripture and various surviving historical records.
“The same historian says that there were also others, descended from one of the so-called brothers of the Saviour, whose name was Judas...” (Eusebius, Church History, 3.32.5)
Notice how Eusebius refers to Judas (Jude) as one of the “so-called” brothers of Jesus, emphasising how they were not considered by the Early Christians as biological brothers of Jesus. The consensus of the Early Church held that Mary remained a perpetual Virgin, adding even more weight to the argument that Jesus did not have any biological siblings. Even Protestant Reformers like Luther, Calvin, Zwingli, and Wesley affirmed the Perpetual Virginity of Mary.
Behold Your Mother:
“When Jesus saw his mother and the disciple whom he loved standing beside her, he said to his mother, “Woman, here is your son.” Then he said to the disciple, “Here is your mother.” And from that hour the disciple took her into his own home.” — John 19:26-27
Following Joseph's death, Jesus as the eldest son would have had the responsibility of caring for His mother. Yet, the fact that at His crucifixion, Jesus entrusted Mary to the Apostle John (the son of Zebedee and Salome) highlights how Mary did not have any biological children, other than Jesus.
We have sufficient biblical and historical evidence affirming that the "brothers" of the Lord were still alive at the time of Jesus' crucifixion. If these were truly biological brothers of the Lord, then it would have been disrespectful of Jesus to give away His mother to an outsider. Yet, rather, it would confirm that Mary did not have any other biological children, which explains why Jesus presents her to John.
The Genealogy Of Jesus' Brothers:
In summary of the biblical and historical evidence provided, Jesus did not have any biological siblings. The “brothers” of Jesus mentioned in Scripture were not Jesus’ biological brothers but were actually Jesus’ cousins from Joseph's side of the family.