Jesus Himself was about thirty years old: This is the only place in the New Testament that mentions how old Jesus was during his public ministry. The number is not exact. Jesus was born between 6 and 4 BC (see study note on 2:2). He began his ministry between AD 27 and 29 (see study note on 3:1). This means he was probably about 31 to 35 years old when he began his public ministry.
He was regarded as the son of Joseph: People understood Jesus to be Joseph’s son. He was Joseph’s legal son, but not his biological son.
the son of Heli: If this passage gives Mary’s genealogy (a family line), as some think (see study note on 3:23–38), then Joseph may have been Heli’s son-in-law rather than his biological son. This is one possible meaning of the Greek sentence.