The seven deadly sins are lust, gluttony, greed, sloth, anger, envy, and pride. Although we usually associate this list with Christianity and especially with Catholicism (the first person to mention such a list is usually taken to be the fourth century Christian monk Evagrius Ponticus, although Pope Gregory I canonicalized the list around 590 A.D.), in fact there might be an Epicurean source for the list. In The Nature of Things, Lucretius (99 B.C. - 55 B.C.) mentions all seven of the deadly sins in two different passages. The first comes near the beginning of Book Three (III.53-74), where ironically he is arguing against religion:
The more harsh that their hardships are, the harder they hold on
To superstition. To truly take the measure of a man,
You must observe him in the midst of trial and tribulation --
Then, from the bottom of their hearts, men say what they believe;
The mask is torn away, and what remains cannot deceive.
Take Avarice and the blind drive of Ambition: both may draw
Wretched men to step outside the limits of the law --
Often even as partners and accomplices in crime --
As each man, day and night, strives harder than the next to climb
Atop the pyramid of power. It is largely the dread
Of death on which these open wounds of life thrive and are fed,
For Vile Disgrace and Bitter Want seem so far from the state
Of a sweet, established life, they almost loiter at Death's gate.
Compelled by an unfounded fear, men, to evade such trouble,
Amass wealth by the blood of civil war, and they redouble
Their riches in their greed, heaping one murder on another.
Stone-hearted, they take pleasure in the sad death of a brother,
And are suspicious of the suppers served up by their kin.
Likewise, Envy, sprung from the selfsame fear, worries them thin...
The second passage occurs near the beginning of Book Five (V.42-55):
And yet what dangers threaten if the mind is not washed clear,
What battles we unwillingly invite into the heart!
How biting are desire's cares that worry man apart,
How menacing the fears! And then consider Pride and Wrath
And Lust -- and the catastrophes which are their aftermath --
And Gluttony and Sloth. And he who's conquered all these, then,
And banished them from the mind -- not by the sword, but by the pen --
Shouldn't he be numbered with the gods and not with men? --
Especially because of the holy wisdom he would preach
Concerning the deathless gods themselves, and since, when he would teach,
He unfolded the whole Nature of the Universe in his speech.
Although we possess only fragments from the writings of "he who's conquered all these" vices (i.e., Epicurus), we do have evidence for these vices as Epicurean "sins", if you will. (Do note that Epicurus, being a good pre-Christian Greek, did not think in terms of sin: the vices he criticizes are more accurately described as negative patterns of thought and behavior based on groundless opinions and unnatural desires.)
On lust (Lucretian spurcitia = "impurity"), the entirety of Epicurean philosophy was designed to encourage moderation or, more precisely, only those desires that are natural and necessary. His is a sober philosophy far removed from the usual caricatures about sybaritic hedonism. Consider:
So when we say that pleasure is the goal, we do not mean the pleasures of decadent people or the enjoyment of sleep, as is believed by those who are ignorant or who don't understand us or who are ill-disposed to us, but to be free from bodily pain and mental disturbance. For a pleasant life is produced not by drinking and endless parties and enjoying boys and women and consuming fish and other delicacies of an extravagant table, but by sober reasoning, searching out the cause of everything we accept or reject, and driving out opinions that cause the greatest trouble in the soul. (Letter to Menoeceus)
As to gluttony (Lucretian luxus = "excess", "indulgence"), it is a sad fact that in modern times Epicurus is thought of as an "Epicure"; yet nothing could be farther from the truth:
Send me a little vessel of cheese, so that I can feast whenever I please. (Fragment 182)
Living on bread and water, I rejoice in the pleasure of my body and spit upon the pleasures of extravagance, not for what they are but because of the difficulties that follow from them. (Fragment 181)
The stomach is not insatiable, as most people say; instead the opinion that the stomach needs unlimited filling is false. (Vatican Sayings 59)
Regarding greed (Lucretian avaritia), Epicurus counselled against the ambition for great riches:
Nothing is enough to one for whom enough is very little. (Vatican Sayings 68)
Natural wealth is both limited and easy to acquire, but the riches incited by groundless opinion have no end. (Principal Doctrines 15)
He who follows nature and not groundless opinions is completely self-reliant. With regard to what is enough by nature, everything he owns is a source of wealth; whereas with regard to unlimited desires, even the greatest wealth is poverty. (Fragment 202)
As to sloth (Lucretian desidia = "idleness", "inactivity"), Epicureanism is often thought of as a kind of lazy philosophy. Yet in Christianity, the primary emphasis is on spiritual laziness, and here Epicurus too emphasizes the importance of continual striving for self-improvement:
Let no one put off the love and practice of wisdom when young, nor grow tired of it when old. For it is never too early or too late for the health of the soul. Someone who says that the time to love and practice wisdom has not yet come or has passed is like someone who says that the time for happiness has not yet come or has passed. Young or old, it is necessary to love and practice wisdom, so that in old age you can be youthful by taking joy in the good things you remember, and likewise in youth you can be mature by not fearing what will come. (Letter to Menoeceus)
On anger (Lucretian petulantia = "impudence", "rudeness"), Epicurus noted that the deathless gods, who lived a life of ataraxia, were utterly without anger:
That which is blissful and immortal has no troubles itself, nor does it cause trouble for others, so that it is not affected by anger or gratitude; for all such things come about through weakness. (Principal Doctrines 1)
On envy (Lucretian invidia), Epicurus wrote:
Envy no one. For good people do not deserve envy, and the more that wicked people succeed the more they ruin things for themselves. (Vatican Saying 53)
On the topic of pride (Lucretian superbia = "loftiness", "conceit", "vanity"), one could argue that Epicurus is less critical than Christianity (he was, after all, pre-Christian). Yet he was no fan of an undue estimation of one's own worth, or disrespect for others:
The study of what is natural produces not braggarts nor windbags nor those who show off the culture that most people fight about, but those who are fearless and self-reliant and who value their own good qualities rather than the good things that have come to them from external circumstances. (Vatican Sayings 45)
We treasure our character as our own, whether or not it is worthy in itself or admired by others; and so we must honor our fellow men, if they are good. (Vatican Sayings 15)
Reportedly, D.E.W. Wormell discusses the connection between Epicurus, Lucretius, and the seven deadly sins in his essay "The Personal World of Lucretius" (1960), but I have not read it yet. It's off to interlibrary loan for me! I might post further, or update this post, when I know more.
UPDATE 2012-11-28: D.E.W. Wormell reports that the Latin words Lucretius uses (spurcitia, luxus, avaritia, desidia, petulantia, invidia, superbia) are not quite the same terms settled on by Pope Gregory (gula, luxuria, avaritia, acedia, ira, invidia, superbia), but they are close and in a few cases poetical or allusive (e.g., spurcitia in the sense of "impure desire", petulantia in the sense of "rude or unjustified anger"). Strangely, Wormell lists ambitio (best translated as something like "the desire for public esteem", "flattery", even "power-lust") as one of the seven deadly sins, overlooking invidia ("envy") despite the passage quoted above from Book Three. It is easy to see why avaritia and ambitio went hand-in-hand for Lucretius (and Epicurus before him) because in those days the greatest wealth was gotten by currying favor with those in political power, but it is invidia (not ambitio) that emerged as one of the canonical deadly sins. Not that the list of vices needs to be limited to only seven, since Epicurus sharply criticizes the "second-handedness" of seeking the esteem of other people and especially those in power, among other behaviors that are based on groundless opinions and unnatural desires.