"In my Father's house"
It’s not surprising that by now the disciples are getting worried! Peter is still so pre-occupied with the bombshell that Jesus is about to go away that the new command to love one another goes completely over his head – all he can think about is, “Lord, where are you going?” (13:33-36). Jesus then adds to Peter’s confusion and anxiety by informing him that he will deny Jesus that very night (13:37-38).
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Though they don’t know it, the fact that Jesus is going away is actually good news. It would be very hard to keep their faith when Jesus lay dead and buried in the tomb, yet he told them to keep on believing (1). The basis for their continuing faith is that his death would not be the disaster that it seemed but would produce huge benefits for them.
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First and foremost, by his death Jesus would open up the way for the disciples to live forever in the Father’s house i.e. in heaven (2). This is the place that he himself is returning to, and he assures them that his going away is to prepare an eternal home for them with the Father. And not only for them – there are “many rooms”, enough for all who will become his followers. By returning to the Father, Jesus opens the way for us to follow him there too.