How would we know if we "dreamed" of Hashem talking to us, but were actually getting Nevuah? Even Shmuel was confused the first time...in fact, he also lived in a time when Nevuah had been withheld ...
In Shemuel I (3:1) the Pasuk tells us that prophecy was a very rare phenomenon. How, then, did 'Eli realize that Shemuel was receiving prophecy and not merely dreaming?
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 ...