Verse For Breaking Free From Hell 
[I] always personally have this thought,
‘With what [can I] enable sentient beings,
[to] attain entry [onto the] unsurpassable path,
[to] swiftly accomplish [the] Buddha’s body?’
– Śākyamuni Buddha
(Dharma [Lotus] Flower Sūtra:
Chapter 16 [On] Thus Come [One’s] Lifespan)
In the ‘Dharma [Lotus] Flower Sūtra Biographies’《法华经传记》is the following record. In Zhēnguàn’s (贞观) third year (630) in the Táng Dynasty (唐朝) at Luòzhōu (洛州), Yú Líntōng (虞林通) gave rose to the aspiration to recite the ‘Dharma [Lotus] Flower Sūtra’ (法华经). However, as his worldly matters were many, he was unable to accomplish so as intended. Thereafter, due to suffering from sickness, he passed away.
Suddenly, there were six hell officials, whom from the front and back surrounded him (i.e. his consciousness). When they reached the gates of the great city of the hells, by its side he met a monastic, who said his name is Medicine King (药王, who was probably a manifestation of Medicine King Bodhisattva; 药王菩萨). He said that although Yú Líntōng’s aspiration to recite the sūtra was not accomplished due to sudden death, he can however, immediately recite one verse, thus teaching him its words, as above.
He explained that if this verse is recited, it is able to transform the hells into lotus ponds, and the bodies with suffering to become Buddha Lands’ bodies (with bliss). Therefore, he should strive to not forget it. Yú Líntōng thus with his utmost recited it to know it well. Then entering the city to meet King Yama (阎罗王), he was asked if he had any meritorious virtues. Yú Líntōng replied that he had no other cultivation of good, only than recitation of one verse.
The King asked what the verse was. When it was recited, where his voice reached, those who were receiving suffering all attained liberation from it, and the 18 ‘departments’ of hells transformed to become lotus ponds. The King asked him to stop, with no need to again recite it, and to sooner return to the human world. Having already passed two days, he then revived, to personally speak in detail of what he saw and heard.
[Original Text (原文): ‘唐洛州虞林通十五：贞观三年。虞林通发心。欲诵法华。俗寰劳务。多不能称素意。遂因患致死。忽有六人冥官。前后围绕。至大城门。傍见有一僧自云。吾是药王也。汝诵经愿。不称其意顿致死。即可诵一偈。教其文曰。每自作是念。以何令众生。得入无上道。速成就佛身。菩萨授偈。谓之曰。若诵此偈。能变地狱为莲华池。能转苦器。作佛界身。努力莫忘。林尽诵通。遂入城中见王。王问。此人有功德不。答无别修善。唯诵一偈。王曰。其偈如何。林诵之声所及处。受苦之人。皆得解脱。十八地狱。变作华池。王曰。止止不须复诵。早还人间。即经二日方苏。说此因缘。祥亲所见闻也。’ -《法华经传记》]
Yú Líntōng received the teaching just in time as he had enough positive karmic affinity to deserve learning it. This is so as he had wished to recite the sūtra that contained it. However, he also had negative karma that led to a shortened life. This reminds us to not spend too much time on the mundane; so as to spend more time for learning and practising the Dharma in time. He probably went to hell first as the general nature of his karma was uncertain or complex, which needed some assessment. It is not that King Yama is his actual judge, but that he can facilitate karmic processes, just as human judges do.
Recitation of the verse is so meritorious that it is able to, at least in the moment, transform the fiery hells’ defiled environment that burn with negative karma, into cool and calm lotus ponds that represent purity. It is also able to transform hell-beings’ bodies with suffering to be blissful, like that of beings in Pure Lands. Such is the power from the asseveration of truth (or satya-kiriyā). By sincerely declaring to assert a moral truth, its merits can bear fruits as beneficial effects. As the verse contains and connects to the essence of the Buddha’s perfect compassion and immeasurable meritorious virtues, his blessings are manifested accordingly.
The verse states that the Buddha(s) are constantly mindful, contemplating on how to use all possible skilful means to guide all beings to escape from suffering, (including from hell), and to enter the supreme path to most quickly attain Buddhahood, thus attaining the Buddha’s form. Use of this verse is one such skilful means.
According to the ‘Sūtra [On] Ten [Methods Of] Rebirth [In] Amitā[bha] Buddha’s Land’《十往生阿弥陀佛国经》, Medicine King Bodhisattva is one of the 25 Bodhisattvas (among many more), who support and protect those who aspire to reach Amitā[bha] Buddha’s Pure Land by mindfulness of his name – ‘Āmítuófó’ (阿弥陀佛). In fact, directly doing so is the easiest and thus most skilful way to escape from hell, and to reach his Pure Land for the swiftest progress to Buddhahood. This is similar in principle to how reciting the verse is also being mindful of the Buddha for his compassionate help.
Interestingly, it is also very meritorious if the verse is sincerely recited from one’s personal perspective, instead of the Buddha’s. It becomes an expression and reminder of Bodhicitta (菩提心), to be selflessly concerned about helping others to walk the swiftest path to Buddhahood. To think the same question in the verse is to be aligned with the Buddha’s Bodhicitta too, making it easier to connect to him.
For these reasons above, the verse is called a ‘Verse [For] Breaking [Free From] Hell’《破地狱偈》. King Yama asked him to stop reciting it, as his newly created meritorious virtues from reciting it, to help himself and many other hell-beings rendered him to no longer deserving stay in hell for an instant longer, while being able to resurrect to continue living longer as a human. The halting also reflected the other hell-beings’ lack of meritorious virtues to deserve rescue then. It was through his return that we are now able to know the efficacy of the verse, to pay special attention to its significance.
The below three verses from the same sūtra are also traditionally called ‘Verses [For] Breaking [Free From] Hell’. Also working with the power of truth, they assert the great truths that Śākyamuni Buddha is already completely liberated from the suffering of rebirth, while he has taken up full responsibility of caring for every sentient being with perfect compassion, as if each is an only child. Due to the great suffering and obstacles we have, with him as our fundamental teacher, he is the immediate one, whose teachings for guidance and meritorious virtues for sharing are capable of protecting and delivering us.
Of course, as all Buddhas are interconnected as one, Śākyamuni Buddha speaks of other Buddhas too, such as Āmítuófó, whom he most frequently urged us to be mindful of. Just as the verse(s) mentioned are calls for help, likewise is mindfulness of the skilfully short yet complete name of Āmítuófó. (Although there are various mantras for the same purpose of breaking free from hell, there is perhaps no shorter one than the name of Āmítuófó, which is already a supreme mantra. Learn about two more related verses at https://thedailyenlightenment.com/2018/12/flower-adornment-immeasurable-life-sutras-verses-for-breaking-free-from-hell.)
Verses For Breaking Free From Hell 
[The] Thus Come [One has] already departed,
[from the] Three Spheres [of Desire, Form and Formlessness]
which are like a] burning house,
peacefully resting, safely dwelling [in] wild forests.
Now, [these] Three Spheres,
all [of them] are [what] I have,
[and] those sentient beings within,
all are my children.
Yet now [in] this place,
[with] much suffering [and] difficulties,
only I one person,
[am] able [to] save [and] protect [them].
– Śākyamuni Buddha
(Dharma [Lotus] Flower Sūtra:
Chapter 3 [On] Parables)
The (Mind-Only) Verses By Forest Of Awakening Bodhisattva
The Flower Adornment & Immeasurable Life Sūtras’ Verses For Breaking Free From Hell
How Mindfulness Of Āmítuófó Protects From Evil Unseen Beings
The Principle Of ‘Vow Now For Birth Now’
The Centrality Of Aspiration Within The Three Provisions
10 Related Sòng Pure Land Sages
Verses For Breaking Free From Hell
The Name Of Āmítuófó Is A Supreme Mantra