Pure Land Practice Method as Advised by Mahasthama Bodhisattva

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Thereat the World Honoured One said to the great Bodhisattvas and chief Arhats in the assembly: 'I want you, Bodhisattvas and Arhats who have practised my Dharma and have reached the state beyond study, this question: "When you developed your minds to awaken to the eighteen fields of sense, which one did you regard as the best means of perfection and by what methods did you enter the state of Samadhi?"'
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Mahasthama, a son of the Dharma king, who was the head of a group of fifty-two Bodhisattvas, rose from his seat, prostrated himself with his head at the feet of the Buddha and declared: 'I still remember that in the remotest of aeons countless as the sands in the Ganges, there was a Buddha called Amitabha who was succeeded by eleven other Tathagatas in that kalpa. The last one was called the "Buddha Whose Light Surpassed that of the Sun and Moon"; he taught me how to realize the state of Samadhi by thinking exclusively of (Amitabha) Buddha. By way of illustration, if a man concentrates his mind on someone else while the latter always forgets him, both may meet and see, but without recognizing, each other. However, if both are keen on thinking of each other, their keenness will grow from one incarnation to another until they become inseparable like a body and its shadow. The Tathagatas in the ten directions have compassion for all living beings and always think of them, like a mother who never ceases thinking of her son. If the son runs away, her thoughts of him will not help. But if he also thinks of her with the same keenness, they will not be separated in spite of the passing of transmigration. If a living being remembers and thinks of the Buddha, he is bound to behold Him in his present or future incarnation. He will not be far from the Buddha and thus without the aid of any other expedient, his mind will be opened. He is like a man whose body, perfumed by incense, gives out fragrance; hence his name "One Glorified by (Buddha's) Fragrance and Light." From my fundamental cause-ground and with all my thoughts concentrated on the Buddha, I achieved the patient endurance of the uncreate. (This is why) I help all living beings of this world to control their thoughts by repeating the Buddha's name so that they can reach the Pure Land. As the Buddha now asks about the best means of perfection, I hold that nothing can surpass the perfect control of the six senses with continuous pure thoughts in order to realize Samadhi.'
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- Surangama Sutta