The man of God said, "Where fell it?" The man who lost the ax head is the only one who could answer that question; no one else knows. It is not "them" but "he." It's an individual matter between the man of God and the one man. "And he showed him the place. And he cut down a stick, and cast it in thither; and the iron did swim."
As soon as the man shows the man of God the place, the man of God cuts down a stick. He would cut it from a green tree; a dead tree would likely be down already. He is not cutting down the tree; he is cutting down a stick. It makes us think of the cross of Christ.
In Scripture man is likened to a tree and in Luke 23:3131For if they do these things in a green tree, what shall be done in the dry? (Luke 23:31) the Lord Jesus says, "If they do these things in a green tree, what shall be done in the dry?" There was only one green tree, and that was the Lord Jesus. The Lord Jesus went into death, even the death of the cross.
The death of the cross was more than just death; it was the kind of death given to a common criminal, especially a slave. It was the type of death Roman society gave a slave who had made himself obnoxious by his crime; they hung him on a cross. They put the Lord Jesus to death that way. Why? Because I deserved it. If that is the kind of death that He died, that is the kind of death I have died, for He took my place. I am no longer associated with that form of life. It is gone, and so the stick reminds us of the cross.