Luke 3:23
Jesus himself, when he began to teach, was about thirty years old, being the son (as was supposed) of Joseph, the son of Heli,
World English Bible (Public Domain)
In context
Before · Luke 3:21–22
21Now when all the people were baptized, Jesus also had been baptized and was praying. The sky was opened, 22and the Holy Spirit descended in a bodily form like a dove on him; and a voice came out of the sky, saying “You are my beloved Son. In you I am well pleased.”
23Jesus himself, when he began to teach, was about thirty years old, being the son (as was supposed) of Joseph, the son of Heli,