Let’s reconsider the question of why the Lotus Sūtra describes Śākyamuni Buddha as the Eternal Buddha. This places Śākyamuni Buddha as eternal not only to unify all the buddhas. The greatest message of the Lotus Sūtra is, “become a messenger of the Tathāgata!”

Teaching extends beyond the physical body. Even if a teacher’s physical body dies, his teachings remain in our memories or in writing. But it is not enough to just remain. A teaching has meaning only when it continues to be taught, actively influencing people. A teaching that is not activated, that does not influence people in the present time, is relatively meaningless. Those who created the Lotus Sūtra were aware of this. They found Śākyamuni Buddha’s one great purpose is to lead all living beings to realize that they can become buddhas, and then with this realization, to walk the path toward achieving buddhahood.

Those who actualize this one great purpose by spreading the message of the Lotus Sūtra through the five practices of bodhisattvas are called teachers of the Dharma and messengers of the Tathāgata. These people activate Śākyamuni Buddha’s great purpose by creating places to work towards the salvation of others as Śākyamuni Buddha had wished, even though they may be living in the buddhaless world that has followed his passing.