Jude was a “brother of James” – probably referring to James who wrote the
letter of James, both of them being half-brothers of Jesus (refer to
Matthew 13:55, Acts 1:14, and I Corinthians 9:5). Some scholars suggest
that Jude may have been the apostle referred to in Matthew 10:3 and Acts
1:13 (also called Lebbaeus or Thaddaeus) but only if he was the brother
of that James and not his son.
He wrote this letter
to the called-people who are loved in God the Father and who are kept in
Jesus Christ.
Scholars suggest that Jude may have written this letter either
between 41-46 AD or much later during the first century.