Exemplarious translation:
１６．〈如來壽量品〉
爾時佛告諸菩薩及一切大眾：「諸善男子，汝等當信解如來誠諦之語。」
是時菩薩大眾，彌勒為首合掌白佛曰：「世尊，唯願說之。我等當信受佛語。」世尊告之言：「譬如五百千萬億那由他阿僧祇三千大千世界，假使有人末為微塵。是諸世界，可得思惟校計知其數不？我成佛已來，復過於此百千萬億那由他阿僧祇卻。
The life span of the Thus Come One (Tathagata-yuspramana)
At that time the Buddha spoke to the Bodhisattvas and all the great assembly:
"Good men, you must believe and understand the truthful words of the Thus Come
One."... At that time the Bodhisattvas and the great assembly, with Maitreya as
their leader, pressed their palms together and addressed the Buddha, saying:
"World-Honored One, we beg you to explain. We will believe and accept the
Buddha's words." ... (The World-Honored One spoke:) "Suppose a person were to
take five hundred, a thousand, ten thousand, a million nayuta asamkhya (i. e. an
uncountable number) thousand-millionfold worlds and grind them to dust... Can
the total number of all these worlds be imaginated or calculated?... The time
that has passed since I attained Buddhahood surpasses this by a hundred, a
thousand, ten thousand, a million nayuta asamkhya Kalpas (life cycles).
譬如良醫智慧聰達。明練方藥善治眾病。其人多諸子息。若十、二十乃至百數。以有事緣遠至餘國。諸子於後飲他毒藥。藥發悶亂宛轉于地。是時其父還來歸家。諸子飲毒。或失本心，或不失者。遙見其父，皆大歡喜。拜跪問訊：『善安隱歸。
我等愚癡誤服毒藥。願見救療更賜壽命。』
Suppose, for example, that there is a skilled physician who is wise and
understanding and knows now to compound medicines to effectively cure all kinds
of diseases. He has many sons, perhaps ten, twenty or even a hundred. He goes
off to some other land far away to see about a certain affair. After he has
gone, the children drink some kind of poison that makes them distraught with
pain and they fall writhing to the ground. At that time the fater returns to his
home and finds that his children have drunk poison. Some are completely out of
their minds, while others are not. Seeing their father from far off, all are
overjoyed and kneel doen and entreat him, saying: 'How fine that you have
returned safely. We were stupid and by mistake drank some poison. We beg you to
cure us and let us live out our lives!'
父見子等苦惱如是，依諸經方。求好藥草色香美味，皆悉具足。
擣篩和合與子令服。而作是言：『此大良藥。色香美味，皆悉具足。汝等可服。速除苦惱，無復眾患。』其諸子中不失心者，見此良藥色香俱好，即便服之，
病盡除愈。餘失心者，見其父，求。雖亦歡喜問訊求索治病。然與其藥而不肯服。所以者何？毒氣深入失本心故。於此好色香藥而謂不美。
The father, seeing his children suffering like this, follows various
prescriptions. Gathering fine medicinal herbs that meet all the requirements of
color, fragrance and flavor, he grinds, sifts and mixes them together. Giving a
dose of these to his children, he tells them: 'This is a highly effective
medicine, meeting all the requirements of color, fragrance and flavor. Take it
and you will quickly be relieved of your sufferings and will be free of all
illness.' Those children who have not lost their senses can see that this is
good medicine, outstanding in both color and fragrance, so they take it
immediately and are completely cured of their sickness. Those who are out of
their minds are equally delighted to see their father return and beg him to cure
their sickness, but when they are given the medicine, they refuse to take it.
Why? Because the poison has penetrated deeply and their minds no longer function
as before. So although the medicine is of excellent color and fragrance, they do
not perceive it as good.
父作是念此子可愍。為毒所中心皆顛倒。雖見我喜求索救療。 如是好藥而不肯服。我今當設方便令服此藥。即作是言：『汝等當知，
我今衰老，死時已至。是好良藥今留在此。汝可取服勿憂不差。』 作是教已復至他國。遣使還告，汝父已死。
The father thinks to himself: My poor children! Because of the poison in them,
their minds are completely befuddled. Although they are happy to see me and ask
me to cure them, thy refuse to take this excellent medicine. I must now resort
to some expedient means to induce them to take the medicine. So he says to them:
'You should know that I am now old and worn out, and the time of my death has
come. I will leave this good medicine here. You should take it and not worry
that it will not cure you.' Having given these instructions, he then goes off to
another land, where he sends a messenger home to announce: Your father is dead.
是時諸子聞父背喪，心大憂惱而作是念：若父在者，慈愍我等， 能見救護。今者舍我遠喪他國。自惟孤露無復恃怙，常懷悲感，心遂醒悟。
乃知此藥色味香美。即取服之，毒病皆愈。其父聞子悉已得差，尋便來歸咸使見之。
At that time the children, hearing that their father has deserted them and died,
are filled with great grief and consternation and think to themselves: If our
father were alive he would have pity on us and see that we are protected. But
now he has abandoned us and died in some other country far away. We are
shelterless orphans with no one to rely on! Constantly harboring such feelings
of grief, they at last come to their senses and realize that the medicine is in
fact excellent in color and fragrance and flavor, and so they take it and are
healed of all the effects of the poison. The father, hearing that his children
are all curd, immediately returns home and appears to them all once more...
諸善男子，於意云何？頗有人能說此良醫虛妄罪不？我亦如是。成佛已來，無量無邊卻。為眾生故，以方便力言當滅度。亦無有能如法說我虛妄過者。
Good men, what is your opinion? Can anyone say that this skilled physician is
guilty of lying?... It is the same with me. It has been immeasurable ... kalpas
since I attained Buddhahood. But for the sake of living beings I employ the
power of expedient means and say that I am about to pass into extinction. In
view of the circumstances, however, no one can say that I have been guilty of
lies or falsehoods.
自我得佛來，所經諸卻數。
無量百千萬，億載阿僧祇。
常說法教化，無數億眾生。
令入於佛道，爾來無量卻。
為度眾生故，方便現涅槃。
而實不滅度，常住此說法。
我常住於此，以諸神通力。
令顛倒眾生，雖近而不見。
Since I attained Buddhahood, the number of kalpas that have passed
is an immeasurable hundreds, thousands, ten thousands, millions, trillions,
asamkhyas.
Constantly I have preached the Law, teaching, converting countless millions of
living beings,
causing them to enter the Buddha way, all this for immensurable kalpas.
In order to save living beings, as an expedient means I appear to enter nirvana,
but in truth I do not pass into extinction. I am always here, preaching the Law.
I am always here, but through my transcendental powers
I make it so that living beings in their befuddlement do not see me even when
close by...
壽命無數卻，久修業所得。
汝等有智者，勿於此生疑。
當斷令永盡，佛語實不虛。
如醫善方便，為治狂子故。
實在而言死，無能說虛妄。
我亦為世父，救諸苦患者。
每自作是意，以何令眾生。
得入無上慧，速成就佛身。
The life span of countless kalpas I gained as the result of lengthy practice.
You who are possessed of wisdom, entertain no doubts on this point!
Cast them off, end them forever, for the Buddha's words are true, not false.
He is like a skilled physician who uses an expedient means to cure his deranged
sons.
Though in fact alive, he gives out word he is dead, yet no one can say he speaks
falsely.
I am the father of this world, saving those who suffer and are afflicted...
At all times I think to myself: How can I cause living beings
to gain entry into the unsurpassed way and quickly acquire the body of a Buddha?
Translated by Burton Watson.