Saturn is considered one of the meanest, strictest and vilest astrological bodies. Its influence is one of restriction, disability, loss of sanity, failing authority and death. What Saturn warns is that we all have a limited time and ways to use that time, so we should expend both carefully and resourcefully.
Saturn returns back to its starting position in the person's natal chart every 28-30 years and that's when we're given the fruits of our labor, both external and internal. If we've exercised enough discipline, the fruits represent wealth, authority and mastery; lack of discipline leads to restrictions, pain and bad karma. In a sense, this moment represents the closing of a cycle, the coming of age in some sense, meaning that the person is nudged to rediscover what it is that is holding it back.
For women, this moment is when they start considering a real relationship and when they "don't want boys but real men" etc. For men, this moment is when they achieve mastery and gain authority of some sort, if that's what they've been building up to throughout their childhood and adolescence or start to experience the yearning to go back to an infantile state. In general, that's when we reap what we've sown.
The harvest symbolism is represented in the archetypal image of the Grim Reaper, a skeleton carrying a scythe. The harvest is done dutifully and with no mercy but no pity either. Another nifty analogy is the barkeep who comes with the bar tab and wants to collect the payment before the party can go on any further. In both cases, we have the idea of facing reality and having to pay our dues.
It's not a surprise that Saturn has to do with death since Saturn is also concerned with limitations and boundaries, as in, infirmity, loss of authority, fall from grace and death. Through legends and myths, we can see the influence of Saturn in its many forms and manifestations.
Ancient artists spent an inordinate amount of time and energy on depicting Saturn. The following painting shows two young ladies and a couple cherubs ripping the wings off of Father Time aka. Grim Reaper aka. Saturn. Note the hourglass on the ground. From an art history perspective, this baroque painting shows the Italian influence in French art. The full title of the picture is "Time Defeated by Love, Beauty and Hope or Allegory of Time and Beauty" and was made in 1627 by Simon Vouet (click the image for a 1,988.89KB, 1920x1486px version).
The following painting by Francisco Goya shows a crazed man biting off the arm from a decapitated child corpse, is titled "Saturn devouring his son" and hails from 1819. I've cropped the picture so it fits better, which means I cropped out the gore but it's still there; if you want to see it, it's shown in the full image (click the image for a 545.9KB, 1616x2889px version).
The main theme of the painting is the myth of a father who is so afraid of losing authority that he kills his sons but he ultimately still loses authority. So, there's the notion of unavoidable fate associated with Saturn as well. The context for that painting states that the man in the picture is Cronus, which gives us another hint—ancient Greeks adopted plenty of astrological myths and molded them into their own cosmology.
Here's another depiction of the same myth, which supposedly inspired Goya. This one also shows an old man feeding on a young boy but was made by Rubens in 1636. I again cropped the gore out of the image (click the image for a 399.54KB, 1418x2952px version).
Now we can already start to connect the dots and see that Satan worship is actually Saturn worship, seeing how satanic rituals supposedly involve child sacrifice, cannibalism etc. All of these themes are already present in Saturn myths and represent a desperate attempt to cling on to power and authority that's slowly but surely fading away.
Despite being widely considered very malicious, or "greater malefic" in astrological jargon, Saturn also provides some favorable influences, if correctly handled. If the person exhibits discipline, Saturn provides indisputable authority, mastery in any given field, bountiful harvest and hidden wealth, which is in line with his mythical attributes of being tied to precious minerals.
Discipline means to stand firm in the face of trouble, to hold the line as the enemy advances and not give in to lower urges. Discipline is steady, dedicated and somber improvement of body and soul, cultivation of the faculties we're given with birth but that lay barren and untilled. Any those who do exhibit discipline are given freedom to do as they please, break as many rules as they wish and still retain authority.
You can see how Saturn symbolism could get twisted into Satan and why there's such an allure in Satan worship. By performing various acts for "Satan", the worshipper expects all the positives without realizing that the relationship has become one of bondage, subservience and limitation, which are the negative aspects of Saturn. Therefore, satanic rituals are actually attempts to find a shortcut that would give all the results without any effort that bind the petitioner to this unbalanced relationship through his own efforts.
On the other hand, we could say married couples constantly remind themselves of marital vows using Saturn, which is represented with a ring, just like the one around the planet Saturn. In that case, Saturn represents dedication, chastity, loyalty in the face of temptations to give in to lower urges and—discipline.
Just like karma, Saturn is perfectly neutral but it's humans that assign it emotional qualities, such as "good" or "bad". Everything Saturn does is meant to show us that our actions have causal effects that go beyond the current moment, stretching into the unfathomable future. Perhaps what we're doing comes back to haunt or bless us, reminding us that we belong in an overarching structure that has ironclad rules that cannot be bent for anyone, except those who show discipline and striving for something better.
No matter where you are or what you're doing, the way forward is always in having more discipline to build an internal force of willpower that can resist random influences. Without making your own framework, one will be imposed on you. Respect your elders, live within your means and work dilligently on the cultivation of your faculties so you can become fully emancipated.