[Sūtra]: Third, [are those who] cultivate practice [of the] Six Mindfulnesses, dedicating [with] giving rise [of] aspiration, aspiring [for] birth [in] that land. Complete [with] these meritorious virtues, [for] one day and even seven days, [they will] immediately attain rebirth.
[Commentary]: Third, [is] explanation [of] those [who] ‘cultivate practice [of the] Six Mindfulnesses’, so-called [being] mindful [of the] Buddha, Dharma, Saṃgha, [and] mindful [of] precepts, generosity, heaven [and] others. These likewise connects [and] agrees [with the] above Third Blessing’s meaning of [the] ‘Great Vehicle’.
Speaking [of] those mindful [of] Buddha, [it] then [is] focused mindfulness [of] Amitā[bha] Buddha’s verbal karma’s meritorious virtues, bodily karma’s meritorious virtues [and] mental karma’s meritorious virtues, [with] all Buddhas likewise thus.
Also [with] wholehearted focused mindfulness of [the] Dharma [that] all Buddhas realised, furthermore all [of their] family members’ Bodhisattva Saṃgha.
Also mindful of precepts [of] all Buddhas, and mindful [of] all past Buddhas, present Bodhisattvas [and] others, [with the] difficult [to] do able [to] do, [the] difficult [to] relinquish able [to] relinquish, [with the] inner relinquished [and] external relinquished. These kind [of] Bodhisattvas, only desire [to] attain [the] Dharma, not sparing [their] bodies [and] wealth. Practitioners [and] others, since mindfully knowing these practices, then must often do [them], admiring [and] learning [the] meaning [of] previous virtuous [ones and] later noble [ones’] relinquishment [of their] bodies [and] lives.
Also, those mindful [of] heaven, then are mindful [of] Tuṣita Heaven above, abiding [in the] last life’s One Lifetime [To] Replacement’s Position’s Bodhisattvas’ meritorious virtues. These Bodhisattvas, [are with] practice of difficult practices already passed, three asaṃkhyeyas of kalpas already transcended, practices of ten thousand virtues already accomplished, [and] Position Of Anointment already realised.
Practitioners [and] others since mindfully knowing, then [should] personally think, ‘Myself [from] beginninglessness since, together [with] others [at the] same time gave rose [to the] aspiration, [to] sever evil [and] practise [the] Bodhisattva path. Others completely [did] not spare [their] bodies [and] lives, [to] practise [the] path [to] enter [this] position, [and] because [of] perfecting [the] fruit, matured [to] realise [as] noble ones. [They] exceed of [the] great earth’s fine [motes of] dust. However, I still am [an] ordinary being, and even today, [am in] vain thus wandering, [with] afflictions [and] evil obstacles, turn [after] turn increasing, [with] blessings [and] wisdom slight, like [being] limited [in sight by] heavy dusk, then facing [a] clear mirror.’
Suddenly pondering this matter, it cannot [be] beared, [with my] mind fearful [and] mournfully sighing!
Sixth, from ‘dedicating [with] giving rise [of] aspiration’ afterwards, [is the] main explanation [of with] each [and every] one, dedicating prior all cultivated karma, dedicating all [for] seeking [that] place.
Seventh, from ‘complete [with] these meritorious virtues’ afterwards, [is the] main explanation [of] cultivation [of] practice’s durations [being] long [or] short. [With those] above exhausting one lifetime, [and those] below to one day, one period, one thought [and] others. Perhaps from one thought, [to] ten thoughts, until one period, one day, [or] one lifetime. [The] main idea [is], once giving rise [to the] mind afterwards, vowing [to, until the] end [of] this life, without having retrogression, only with Pure Land [when reached] as [the] date [for ending].
Also speaking [of] those ‘complete [with] these meritorious virtues’, perhaps [with] one person complete [with the] two above, perhaps one person complete [with the] two below, perhaps [with] one person [with the] three kinds all complete. Perhaps having persons, those [with the] three kinds without [any] part, [who are] named as ‘animals wearing human skin’, not named humans. Also not questioning [being] complete [with the] three [or] not complete [with the] three, dedicating completely, [they will] attain rebirth. [This] should [be] known.
Pure Land Tradition’s 2nd Patriarch Great Master Shàndǎo
(Commentary [On The] Contemplation Sūtra [In] Four Fascicles: Scroll Four: Scattered Goodness’ Meaning)
Summary: The third kind of beings who reach Pure Land are those who cultivate the Six Mindfulnesses, mainly by being mindful of the Triple Gem (三宝) in terms of  all of Amitābha Buddha meritorious virtues,  all his related Dharma teachings and  all his Saṃgha members, such as Contemplator Of The World’s Sounds (观世音), Great Power Arrived (大势至) and other Bodhisattvas in his lotus pond ocean-wide assembly (莲池海会). Also by being mindful of the  Bodhisattva Precepts,  practices of generosity and  the greatest Bodhisattvas’ meritorious virtues on the brink of Buddhahood, also as attainable most swiftly via reach of Pure Land. All the above practices, be they little or much, are thus all dedicated with the aspiration for birth in Pure Land.
Namo Amituofo : Translation and summary by Shen Shi’an
What Is The First Kind Of Beings Who Reach Pure Land?
What Is The Second Kind Of Beings Who Reach Pure Land?