Śāriputra, who felt like dancing with joy …

From this phrase to the beginning of [the parable of] “the burning house” there are altogether three segments explaining the purport. The first [segment] explains that Śāriputra has achieved understanding within himself and issues outward what he has comprehended. Because his doubts, arisen earlier, were serious, his anxiety and worry were very deep. Now, the first [among the congregation] enlightened to the One Vehicle, he expressed his pleasure, saying that he wanted to dance for joy. Unable to get over his pleasure, he could not help saying so. It is shown here that, by resort to the traces, [the Buddha] exigently draws [the attention of] the congregation of the moment, making the collective sentiment at the time deeply earnest.