Jonas and the Giver agree that the community needs to have all the memories of happiness, sadness, joy, and pain that had previously been held by the Giver and Jonas. The way to make this happen is for Jonas to leave the community, because once he does, all the memories he has will be released into the community. The Giver will stay because the community can't bear all the memories that both of them have, and to help the community deal with the pain.
The plan is for Jonas to wait for the naming ceremony to begin, and then to go to the Giver. The Giver will give him memories of happiness and courage to give him strength, and then he will sneak out of the community without anyone knowing and leave.
However, Jonas finds out that Gabe is scheduled for release and instead decides to escape that same day. He doesn't have time to go to the Giver, so he just finds Gabriel and then takes his father's bike. Stealing the bike wasn't his original plan, but he needs a bike with a child seat, so he feels that he has no choice. Jonas and Gabe then leave the community and do not return.