One of the leaders told Jonas that he was the Receiver of Memory.
Road of Trials
Dont' speak of anything that happens in training.
the color red, I saw blood and war...
Jonas doubts himself that he could be The Receiver Memory. He doesn't want to feel the pain that they usually get.
Jonas gets his first memory passed down from the giver. Which was when he was have so much fun on the sled in a snowy day.
Jonas sees his first color which was red and when The Giver gave him the memory, Jonas thought it was love, but it was blood, pain, and war. In the memory, he was on the sled again. He fell and broke his leg.
The connection between Jonas and The Giver is like grandfather and son.