Shalit's family pleaded with the captors Monday to treat him humanely and to remember he has a loving family who misses him dearly.
Noam Shalit, in an interview with AP Television News, described his son as a quiet, helpful boy who followed his older brother into the military's armored corps.
"The only thing we have left right now is hope, nothing more," he said.
In Gaza City and the West Bank town of Ramallah, dozens of relatives of Palestinians held in Israeli prisons urged militants to hold Shalit until Israel agreed to a large-scale release.
"Kidnap a soldier and free 100 in return!" the crowd said. "Twist the Zionists' arms! Hope they can learn!"