At first, Bono tried writing from the perspective of Suu Kyi's husband and son, imagining them living with the pain of not knowing how she was. Feeling that it seemed presumptuous, Bono changed the lyrics to be more abstract and to be "a love song about somebody having to leave a relationship for all the right reasons". He said the song was about "nobility and personal sacrifice, about doing what's right, even if your heart is telling you otherwise." In explaining the lyrics, he recalled a Biblical passage in Corinthians that used the image of a house fire to impart the lesson that only eternal things can survive. To Bono, these things were family and friendships, rather than anything that someone could concretely make. Accordingly, "Walk On" concludes with lyrics describing a "litany of ambitions and achievements" that are expendable, with lines such as "You've got to leave it behind / All that you fashion / All that you make / All that you build / All that you break". Bono described this section as: "a mantra, really, a bonfire of vanities, and you can throw anything you want on the fire. Whatever you want more than love, it has to go." The album's title was derived from the song's lyrics "The only baggage you can bring is all that you can't leave behind."