Today's first reading is the classic vocation story. In fact, in all the religious professions I have ever been to, the novices repeat the words the old priest Eli taught Samuel to say, "Here am I, Lord."
The interesting thing in the story of Samuel is that God kept on calling him, but little Samuel didn't recognize who was calling his name. He kept mistakeningly running to Eli's bedside, and the blind priest kept dismissing him as a cute little boy who was having vivid dreams. Finally, Eli himself "woke up" to what was going on, and acted as a wise spiritual director, helping Samuel to respond to an experience that Eli himself may never have had.
In the Gospel, Jesus shows us another side of discernment. He had been mobbed by the people of Capernaum, all of them needing healing for themselves or a loved one. In the morning, he was the first one out of the door, before anyone else was even up. Off he went to a secluded place to pray. When the disciples, predictably, came looking for him (the Greek indicates that they "hunted him down" like some sort of quarry), to bring him back to town for more manifestations of power, Jesus did not assume that this was God's call. Instead, he told them to get ready to leave for other towns: "For this is why I was sent."