Avraham stands at the entrance of his tent after his Brit - Bereshit 18 - looking around he sees three men at a short distance (even getting closer).
At a certain point they ask Avraham: “Where is your wife Sarah?” Avraham replies: “See (here) in the tent.”
Then one of the men (he) says: “I will return to you and your wife Sarah will have a son.” Sarah was listening from the tent and as a reaction she starts to laugh.
Then in verse 13 it says that G-d replies to this by saying: “Why did Sarah laugh?”, “Is anything too difficult for G-d”? At the designated time, I will return, and Sarah will have a son”
So here is my question: is the he really one on the men? Or is it G-d who speaks from the beginning or through his messenger? Because these messengers seem to be close to the tent and hear Sarah laughing. And ‘he’ says: I will return, while later it’s clear G-d says He will return. And again in Genesis 21:1 this seems to be the case. We read nothing of one of those men (who were malachim) returning right? So how could one of them says: I will return?
How do I need to explain these things?