Barry went back into the Speed Force to save Wally from the prison Savitar sent him to last week on The Flash. In "Into the Speed Force," Barry faced Eddie (Iris' ex-fiancé), a few time wraiths, Ronnie (one half of Firestorm), and Leonard Snart (aka Captain Cold) on his quest to break Wally free from the Speed Force prison. But, once Barry found Wally, he couldn't get to him. Not until Jay Garrick showed up and saved the day. Jay not only helped Barry face off against Captain Cold, he took Wally's place in the Speed Force prison. After Jay sacrificed himself for Wally, many wondered, is Jay Garrick dead on The Flash?
Don't freak out, Flash fans, Jay isn't dead. At least, not yet. Just like Wally last week, Jay isn't so much dead as he is trapped in eternal misery courtesy of the Speed Force. As Savitar explained when he captured Wally, the prison cannot be empty, it must be occupied by a speedster. Savitar needed Wally to take his place in the prison so he could escape, and now Jay has sacrificed himself to take Wally's place. Barry promised he'd come back for Jay, but their goodbye felt pretty final. "You need to end this once and for all and stop Savitar," Jay told Barry before reminding him that he could beat Savitar just by being the Flash.
Jay's appearance allowed Barry to take Wally out of the Speed Force, something Barry saw as crucial to saving Iris. But, during his time in the Speed Force, Barry learned a lesson: he had to defeat Savitar. Savitar was his responsibility, and the Speed Force wants Barry to go up against the self-proclaimed Speed God, not Wally. Barry went into the Speed Force planning to take Wally's place in the prison, which is why the Speed Force sent Eddie, Ronnie, and Snart to stop him. But, once Jay appeared, the Speed Force let Barry take Wally home.
Even though Barry is now taking on saving Iris as his responsibility, and his alone, there's no doubt that having Wally on hand will be an asset against Savitar. Barry might not be fast enough to save Iris right now, but with Wally's help, he could be one day, and that's good enough for me.