Upon hearing the Blessed One expound on his eternal-lifespan, the Lotus Sutra goes on to explain in the ensuing chapters how immeasurable sentient beings may draw merit from this realization.
(from Chapter 17) At that time the Buddha addressed Bodhisattva Mahāsattva Maitreya, saying: “O Ajita! Those sentient beings who hear about the great length of the Buddha’s lifespan, and can awaken even a single thought of willing acceptance, will all obtain immeasurable merit. If there are sons and daughters of a good family who, for the sake of highest, complete enlightenment, practice the five perfections of giving (dāna), good conduct (śīla), perseverance (kṣānti), effort (vīrya), and meditation (dhyāna), with the exception of the perfection of wisdom (prajnā), for eighty myriads of koṭis of nayutas of kalpas, their merit is not even a hundredth, a thousandth, a hundred thousandth of a myriad of a koṭi of the former person’s merit. It is so small that it cannot be conceived of through calculation or illustration. If there are sons and daughters of a virtuous family who possess such merit as the former, they will never revert from highest, complete enlightenment.”
Quite an astounding revelation! Even those bodhisattva-families who faithfully practice the six paramitas for limitless-myriads of time, will not even come close to the merit that is bestowed upon those former fortunate ones who have heard it proclaimed in the Lotus Sutra: the Supreme Nature of Śākyamuni’s lifespan as a Tathagata “and who can awaken even a single-thought of willing acceptance”. This truly shows the extent of how high a premium is placed on the salvific expediency of this text. Chapters 18-21 continue in this vein, displaying the countless merits that are bestowed upon those who revere this most illustrious Lotus. This reaches a climax in the brief, but poignant, 22nd Chapter; it is here that the Buddha displays his own seal of approval.
Thereupon, having arisen from the Dharma seat and manifested his great transcendent powers, Śākyamuni Buddha caressed the heads of the innumerable bodhisattva mahāsattvas with his right hand, and addressed them, saying: “For immeasurable hundreds of thousands of myriads of koṭis of incalculable kalpas, I practiced this Dharma of highest, complete enlightenment, which is hard to attain. I now entrust it to you. You should wholeheartedly spread this teaching and so extensively benefit others.”
Having caressed the heads of the bodhisattva mahāsattvas three times in this way, he further addressed them, saying: “For immeasurable hundreds of thousands of myriads of koṭis of incalculable kalpas, I practiced this Dharma of highest, complete enlightenment, which is hard to attain. I now entrust it to you. You should preserve and recite it. You should spread this teaching extensively. You should let all the sentient beings hear and know it. Why is this? Because with his great compassion, unstinting and unafraid, the Tathāgata gives the wisdom of the Buddha, the wisdom of the Tathāgata, and the knowledge of the self-arising one to the sentient beings. The Tathāgata is nothing but the great donor to all the sentient beings. You should accordingly practice the teaching of the Tathāgata. Never allow the thought of avarice to awaken in you! If there are sons and daughters of a virtuous family who believe in the wisdom of the Tathāgata in the future, you should expound this Lotus Sutra; and let them hear and know it so that they may attain the wisdom of the Buddha. If there are sentient beings who do not accept it, you should reveal, teach, benefit, and gladden them with the other profound teachings of the Tathāgata. If you do this, you will repay your indebtedness to the Buddha.”
The Tathagata has actually performed a ceremony of anointment, a most profound and eminent sign of marking and sending his loyal bodhisattvas out in order to propagate the Lotus Sutra. Similar anointments have occurred in other Sutras, most notably articulated in the Lanka series:
The Lanka describes a beautiful mystical transformation that occurs when the bodhisattvas reaches the tenth-stage, or dharmamegha (dharma-cloud): “As they work their way through the easy and difficult aspects of the various stages, they finally reach the dharma cloud stage, where they dwell inside a magnificent lotus flower palace seated upon a jeweled lotus flower throne surrounded by a retinue of their fellow bodhisattvas adorned with necklaces of jewels that shine like the sun or the moon or golden champaka flowers. The great victors of the ten directions then appear before their thrones in this lotus flower palace and anoint their foreheads…
A similar propitious moment can be found from in Chapter 26, the Ten Grounds, of the Avatamsaka Sutra:
To receive all Buddhas’ Anointment of one’s crown; having all the Buddhas of the ten directions and the three periods of time come and give you a prediction and rub your crown to aid you; in order TO PERFECT THE WISDOM OF ALL-WISDOM, perfecting the very ground of all wisdom and then enabling all living beings to obtain the wisdom among wisdoms.
Yes, this is THE special-mark of the Tathagata, highlighting that an ineffable moment has just transpired and assuring success in the propagation of the Buddhadharma. This also is the Buddha’s Way in the Lotus Sutra of “sealing” its auspicious mark for all time.