The origin of suffering, as a noble truth, is this: It is the craving that produces renewal of being accompanied by enjoyment and lust, and enjoying this and that; in other words, craving for sensual desires, craving for being, craving for non-being.
While in this particular verse, Buddha refers to craving or grasping as the origin of suffering, recall that in the previous verse he also mentions aversion as "association with the unpleasant" and ignorance as "the five aggregates of attachment" or "to grasp the Five Aggregates as though they constitute a self." These poisons (kleshas) produce our desire to continue (either in this life or through further reincarnations), our facile enjoyment in continuing, and our attachment to the pleasures that keep drawing us back, even though they only give temporary relief and enjoyment (including the aversion to things that we think will interfere with these). These can each be fruitfully examined in more detail (though there is a lot of overlap as these principles inter-are):
Our Desire to Continue: in our usual state we all fear our own death, or own non-continuation in life. It is something that we continually avoid thinking about, so we seek near constant distraction: through TV, music, activities, books, parties, shopping, eating, drinking, drugs, and sex. It is behind emotions such as anger, boredom, fear, listlessness, and the Western favorite of existential anxiety (the feeling of profound groundlessness). This is primarily because we think that in death we cannot continue enjoying that which we crave: we will not 'have the chance' to reach that "just one more this or that and I'll finally be happy" that is always escaping us (and always will). This can also refer to not wanting the passing away of that which we wish would stay: that the pleasant always has an end and, in some cases, can turn into its opposite, pain.
Our Enjoyment in Continuing: when we continue we can continue to enjoy our various pleasures. So our continuing will most likely increase our continued enjoyment, or so we like to think. Though this is our desire and it is true that we can and do experience pleasure in our lives, this is only one side of the three-sided coin, the side that we fixate on.
Our Attachment to that Which Inevitably Fades: We all desire pleasure in our lives. But because the nature of reality is that of impermanence, our pleasures always fade, oftentimes turning into pain: indigestion, withdrawal symptoms, exhaustion, hangovers, etc. Ironically, this impermanence is exactly what spurns us on: we want more pleasure when it fades and we want things that we don't have; when we get what we want and it doesn't last, we seem to think that the next thing will give us lasting happiness, though, by its nature, it is incapable of causing this result (like cold cannot cause water to boil). So our lives are punctuated by an endless cycle of desire, satiation, lack, and the inescapable return of desire. So we desire that which is no longer or is not yet (non-being).
These are the causes of our suffering and, in order to live and realize the Second Noble Truth, we need to see how these play out in our own lives. Only then can we hope to let go of the causes of our suffering.
