This is another attempt by Manoah to control the visitor. It was commonly thought in the ancient Near East that knowing the name of a heavenly being gave the person power over that being. Someone’s name was closely related to who they were. This is part of the reason why the Lord was very explicit on using his name properly. Manoah, therefore, is still looking to have manipulative power through special knowledge.
1 And so the visitor, by his question in Judges 13:18, reveals an unwillingness to release his name for Manoah control.
17 And Manoah said to the angel of the LORD, “What is your name, so that, when your words come true, we may honor you?”