John Gill Commentary Judges 13:21

"But the angel of Jehovah did no more appear to Manoah or to his wife. Then Manoah knew that he was the angel of Jehovah." — Judges 13:21 (ASV)

But the angel of the Lord did no more appear to Manoah and to
his wife
As the flame and smoke ascended, he disappeared therewith, and was seen no more:

then Manoah knew that he was an angel of the Lord ;
by the wondrous things he did, causing fire to come down from heaven, or out of the rock, ascending in the midst of the flame, without being hurt by it, and going up to heaven in it.