Judges 13:21 a.
‘And the angel of Yahweh did not appear any more to Manoah or to his wife.'
Once the Angel had ascended in the flames He appeared no more. His visitation was over.
‘Then Manoah knew that he was the Angel of Yahweh.'
When Manoah saw the Angel of Yahweh disappear in the sacrificial flames he knew Whom He was, and that they had been face to face with God..