From Desiring God:
We know very little about Jesus’ childhood. But as I’ve been meditating recently on what it must have been like growing up having Jesus as a sibling, I can’t help but wonder what it must have been like for him.
We know that Jesus’ own brothers didn’t believe in him (John 7:5), possibly until after his resurrection (Acts 1:14). Could some of Jesus’ experience of rejection and grief possibly have resulted from estrangement he experienced in his own family simply because he was without sin?
He was a perfect child living with sinful parents, sinful siblings, and sinful extended relatives. The difference between him and them must have become increasingly apparent and awkward. Sinners can be cruel to those who are different from them, especially if envy infects their cruelty.
Sometimes we feel alone in the world. But in a very real sense, Jesus was alone in the world. No person on earth, much less in his family, could identify with him. No human being could put an arm around him as he sat in tears and say, “I know exactly what you’re going through.”
I’ll bet Jesus understands loneliness far better than we might think.