It refers to the three kinds of pure karma practiced by those who are reborn in the Pure Land of Ultimate Bliss; this is the cause of the pure karma of the Buddhas in the past, present and future three times.

That is: (1) Blessings in the world and doing good deeds in the world.

The good laws of filial piety, loyalty, and trust that originally exist in the world, such as being filial to parents, serving teachers, being kind and not killing, and practicing the ten good deeds, etc.

(2) Precepts are blessings, and precepts are good.

The precepts prescribed for the Buddha's birth include the Three Returns, the Five Precepts, and even the full precepts accepted and upheld by humans, gods, voice-hearers, and bodhisattvas, as well as not violating the majestic etiquette.

Among them, some may have feelings or not; some may have upholding or not, but if they all dedicate themselves to it, they will surely be reborn.

(3) Perform blessings and do good deeds.

Arouse the Mahayana mind for ordinary people, and transform the good roots they have by themselves, that is, develop the great Bodhicitta, firmly believe in cause and effect, read and recite Mahayana scriptures (enlighten wisdom, hate suffering and appreciate Nirvana), encourage practitioners (persuading people to abandon evil and move towards the path of Nirvana), and make vows

Rebirth in the Pure Land, etc.