ב"ה I have heard this idea, but I could never find a source for it. The idea is that in certain circumstances when the Torah uses the word ואמר referring to Hashem speaking that it means that the ...
In Shmeul Aleph Perek Gimel Shmuel becomes a Navi. Pasuk Gimel Pasuk Daled it says that Hashem called to Shmuel and he(Shmuel) said Hineni. But them Pasuk Hey continues by saying the Shmuel ran to ...