From Nagarjuna's Treatise on the Great Perfection of Wisdom
(Dharmamitra Translation)

Question: If it is the case that eight moral regulations and pure livelihood collectively constitute the precepts, why is there no mention for the upaasaka of either the other three moral regulations associated with the mouth or of pure livelihood?

Response: The white-robed householders accept the pleasures of the world while also concurrently cultivating merit. They are unable to fully practice the Dharma of the precepts. Therefore the Buddha ordered that they uphold the five precepts. Moreover, within the four moral regulations associated with mouth karma, false speech is the most serious. Additionally, with false speech, the thought arises and then one deliberately engages in it. As for the others, perhaps one deliberately engages in them or perhaps one does not deliberately engage in them. Then again, when one only mentions false speech, one already subsumes therein the other three matters. Moreover, within all of the good dharmas, truth is of the greatest. If one speaks true words, the four kinds of right speech are all entirely subsumed and realized. Additionally, the white-robed layperson abides in the world where he assumes the role of overseeing and management. He takes responsibility for the family business and issues orders. Hence it is difficult to uphold the dharma which requires not engaging in harsh speech. False speech is a thing which is intentionally done. Because it is a serious matter one should not engage in it.

There are five degrees of acceptance of the five precepts which determine the five kinds of upaasaka. The first is the single-practice upaasaka. The second is the lesser-practice upaasaka. The third is the greater-practice upaasaka. The fourth is the full-practice upaasaka. The fifth is the celibate upaasaka. As for the first, the single-practice upaasaka, it refers to taking on one precept from among the five precepts while being unable to take on and uphold the other four precepts. As for the lesser-practice upaasaka, it refers to taking on two or three precepts. The greater-practice upaasaka refers to taking on four precepts. The full-practice upaasaka refers to completely upholding the five precepts. As for the celibate upaasaka, after taking on the five precepts, in the presence of his [spiritual] teacher, he additionally makes a vow for himself, saying, "I will no longer engage in sexual activity even with my own wife. This is what is meant by the five precepts.

The Buddha's Verse on the Five Precepts and Their Karmic Rewards

From Nagarjuna's Treatise on the Great Perfection of Wisdom
(Dharmamitra Translation)

One does not kill and does not steal,
Nor does one engage in sexual misconduct.
One maintains true speech and does not drink alcohol.
One upholds right livelihood and thereby purifies his mind.

If there is one who is able to carry this out,
In the two periods of time, worry and fear will be gotten rid of.
The merit of the precepts will constantly follow along with him.
And he will always be together with gods and men.

In the six-seasoned flower of the worldly existence,
Glory and physical form bloom together.
One can find that this single flower of years,
Is contained in one day in the heavens.

The heavenly trees spontaneously produce
Flower garlands and necklaces.
The red flowers there are luminous like a lamp.
The many colors are interspersed among each other.

The heavenly apparel of incalculable varieties
Possesses hues of so many sorts,
Displays a fresh whiteness reflecting the heavenly sun,
And is light, closely-woven and free of wrinkles.

The golden light is reflected in embroidered patterns.
The graceful patterns of color are like the airy formations of clouds.
The supreme and marvelous apparel like this
All comes forth from heavenly trees.

There are bright jewels and celestial earrings,
And precious bracelets brighten the hands and feet.
Whatever the mind finds delightful
Also comes forth from the heavenly trees.

There are flowers of gold with stems of vai.duurya
With vajra making up the floral stamens and pistils.
They are soft and pliant with a fragrance which pervades.
They all come forth from pools of jewels.

The guitar, bass, harp and lute
Are inlaid with ornaments of the seven precious things.
The instruments are marvelous, the ancient sounds are clear.
All of these also come forth from the trees.

The paarijaataka tree
Is the king of trees in the heavens.
They grow in the gardens of delight.
And are unmatched by any others.

Upholding the precepts is the tilling of the fields.
The heavenly trees come forth therefrom.
The sweet dew flavor of the celestial kitchens:
Its drink and food dispel hunger and thirst.

The heavenly maidens have no interference from guardians,
Nor do they have the difficulty of a body which becomes pregnant.
One can play and relax and indulge without restraint in the pleasures.
Eating is free of the troubles of elimination.

If one upholds the precepts and constantly restrains the mind,
One succeeds in being born in a land where one may indulge.
There are no tasks to be done and there are no difficulties.
And one always fulfils aspirations to enjoy one's pleasures.

All of the gods achieve sovereign independence.
Distress and suffering no longer arise.
Whatever one desires comes in response to one's thoughts.
The light from one's body illuminates any darkness.

All sorts of such pleasures as these
All come from giving and the observance of precepts.
If one wishes to gain this reward,
One ought to be diligent and exhort oneself.

Why the Heavenly Rewards of the Five Precepts are Praised

From Nagarjuna's Treatise on the Great Perfection of Wisdom
(Dharmamitra Translation)

Question: Now we are discussing the shiila paaramitaa. It should be for the purpose of realizing buddhahood. Why is there now this praising of the merits of the heavens?

Response: The Buddha said that there are three things which will certainly be gained and for which the result which comes as a reward is not false: If one gives, one gains great fortune. If one upholds the precepts, one will be reborn in a fine place. If one cultivates the absorptions, one will gain liberation. If one solely practices shiila, one will succeed in being born in a fine place. If one carries forward the combined practice of the absorptions, wisdom, loving-kindness and compassion one gains the way of the Three Vehicles.

Now we are solely praising the upholding of precepts. This brings meritorious qualities, fame, peace and bliss in the present life and in later lives one gains rewards such as were praised in the verse. This is analogous to smearing honey on bitter medicine for a small child so that afterwards he is able to swallow it. Now we first praise the merit from the precepts so that afterwards a person is able to uphold the precepts. After one has been able to uphold the precepts he makes the great vow to succeed in arriving at the Buddha Way. This amounts to shiila producing shiila paaramitaa.

Also, because all people are attached to bliss and because among all of the world's blisses, those in the heavens are the best, if they hear of all of the various sorts of pleasure and happiness in the heavens, they will then be able to take on the practice of shiila. Later, when they have heard of the impermanence of the heavens, thoughts of aversion and abhorrence will develop and they will be able to seek liberation. When they additionally hear of the incalculable meritorious qualities of the Buddha, it may be that thoughts of loving-kindness and compassion arise whereby they may rely upon shiila paaramitaa to succeed in arriving at the Buddha Way. On account of this, although we speak of the rewards associated with shiila, there is no fault in it.