Cultus
Cultus, meaning “care, cultivation, worship,” is the worship of a deity, which requires knowledge of giving said deity Their proper due. This implies active maintenance beyond mere passive adoration, and is typically in the form of traditions with correctly performed rites and ceremonies that worshipers engage in to “cultivate” the benevolence of the Gods as a means of bringing us closer to Their divine light (Adkins 2005, 309) (Sallustius, XIV). The concept deeply ties to religio (the service that mortals render to the Gods), which is nothing other than the proper cultus of a God.
A God’s cultus indicates everything regarding the worship of that divinity, from cult images, to temples, myths, holy sites, pilgrimages, hymns, sacrifices, personal devotion, and so on. A God is not merely the object of veneration in Their cultus, but rather They are the very source of Their own cultus, and play a role of active advocation for it. All cults were established through divine inspiration, such as the cultus of Lord Serapis, who had revealed Himself to the city of Sinope and later the divine Ptolemy Soter. Once His sacred icon was retrieved under orders of the Pharaoh and brought before the Greek and Egyptian priesthoods in Alexandria, the priests, through divine inspiration and synthemata, came to discover and understand His cultus (Lankila 2016, 150-151). Other times, some specific cultus were established by intentional human agents with divinely-inspired souls who were sent forth from the Gods (Lankila 2016, 151). Semele, for example, was the first Prophetess who perceived the forthcoming of Dionysos, and gave signal of the mystic rituals connected to the God (albeit too early) (Flavius Claudius Iulianus, II 70). Orpheus is another example, who had been a philosophical prophet who acted as the founder of Orphism (Lankila 2016, 151).
These divine origin of a cultus means that since the authentic kernel of the cultus is immortal, being divine and thus always healthy, a part of the cultus is incorruptible and therefore any damage a cultus suffers during the course of history is consequently repairable (Lankila 2016, 150). This divine part of the cultus is forever eternal and unchanging. It is always present, and it is something that cannot be changed or tampered with. However, practice tends to be part divine and part mortal, and while the divine part cannot be changed, the mortal part is subject to reform, and therefore a certain degree of innovation is allowed in proper cultus (Lankila 2016, 150). If traditional forms are seen as faulty, they can be replaced by what is perceived as more proper, and simultaneously authentic traditions can be resurrected where they are absent (Lankila 2016, 149). This is thanks to Platonic scientific theology which allows adequate knowledge of the divine, which is done through dianoia (the capacity for discursive thinking) and theourgia (communion with the divine through experience) (Lankila 2016, 159).
Since a God’s cultus has divine origins it is itself ingrained in theurgic activity, and as such by engaging in it via the correct observance of rituals, we imitate the divine and thus bring real changes to ourselves which allow us to become more like the Gods. This cleanses ourselves of sins and ritual impurities which normally pollutes and distracts us from attaining gnosis. The true spiritual wisdom attained through praxis manifests as pathos, or spiritual enlightenment.
Piety
“Zeal to do all that is in one’s power is, in truth, a proof of piety, and it is evident that he who abounds in such zeal thereby displays a higher degree of piety; whereas he who neglects what is possible, and then pretends to aim at what is impossible, evidently does not strive after the impossible, since he overlooks the possible.”
-Julian the Philosopher (Flavius Claudius Iulianus, II 311)
Piety (Latin: Pietas, Greek: Eusebeia) is a something that is essentially “dutifulness,” and is paying proper honor to the Gods. It is concerned with deeds regarding moral issues, the natural order, and the maintenance of devotion towards family, friends, ancestors, your fellow man and the Gods (Adkins 2005, 309). Furthermore, it is done through the correct practice of rituals. The concept of piety goes hand in hand with kharis. While kharis is the reciprocity and the religious relation that comes from practicing piety, piety is the actual practice of worship through actions (typically sacrifice and properly performed rites) and building one’s kharis with the divine (Baring the Aegis, 2012).
When one approaches the Gods, they must show their piety and receptiveness (Xenia) and always recognize their place in the cosmos (Aidos). Piety improves the condition of the soul by elevating it towards the Gods (Sallustius, XIV). To elevate our souls upwards to them, we expose ourselves towards Their divine radiance through offerings, prayers, meditation, hymns, worship through images, invoking divine presence, etc. In other words, we use piety to engage in cultus (Deo Mercurio, Philosophy in Gaul).
Filial Piety

Aineías escaping from Troy, carrying his father Ankhises on his shoulders and giving his hand to his son Askanios, 1st century CE.
[To Be Filled]
Bibliography
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