…at least in the way one may think it is.
When the Jedi Order and its teachings are discussed, it's common to talk about a Jedi religion, faith, dogma, tradition, expectation of celibacy, obedience, belief in having a divine mandate, church, teaching individuals the acceptance of doctrines from early as birth, and the idea that Jedi Knights are viewing themselves as the hands and eyes of the divine, trusted to carry out its will.
The series of teachings given by Jedi Knights in George Lucas’ Star Wars story, encompassed by the six feature films and the six seasons of the Clone Wars, although describes a nonmaterial, spiritual reality, addresses what happens after we die, it's down-to-earth practical - it's not religious, but spiritual, built on rationality, rather than on faith and belief, holy scripture, institution, or principles laid down by an authority as incontrovertibly true, or worship of a deity, or performing rituals and prayers. Nor there is any mention that a Jedi Knight is supposed to take a vow of celibacy, or that they hold themselves to be knowers or messengers of the will of the Force, or that they have a belief system that they institutionalized as a political and social force. It's about us, our minds, and our and other's well-being - it's about being, rather than believing.
UNDERSTANDING THE WAYS OF THE FORCE
The spiritual reality in George Lucas' Star Wars is, the Force: it's life itself, a metaphor for God and for a belief in God; it was based on a concept of the transcendent reality Lucas himself believes in, and it was designed to awake a sense of spirituality in young people. It's life itself, encompassing, but also going beyond the individual life forms.
When one is alive, through their vessel of crude matter, the universal life force, consciousness, spirit, soul circulates, bringing them the experience of individual, separate life, composing individuality and persona. When one dies, the Force recedes from this vessel, and all that one is - life force, consciousness, spirit, soul, self, everything - is rejoining with the entirety of the universal Force, that is all-powerful, creator, destroyer, governs everything and sets destiny. Knowing the ways of the Force is knowing yourself and knowing reality.
BEHIND ALL EVIL, THERE IS ALWAYS FEAR
In the first trilogy, Obi-Wan "Ben" Kenobi identified the culprit behind Darth Vader's fall and evil actions: the dark side of the Force. As Yoda revealed, “Anger, fear, aggression… the dark side of the Force are they”, and giving in to hatred led to a life lived on one's dark side. Luke Skywalker relied on these teachings in Episode VI, when he recognized, his dark side is leading him on a path that ends in Darth Vader's armor. He refused to give in to it, and he was able to redeem his father by relying on love, compassion, generosity and hope.
How these feelings and emotions are arising and functioning in our lives is explored in the second trilogy. As Yoda explained to Anakin Skywalker, "fear is the path to the dark side" because "fear leads to anger, anger leads to hate, hate leads to suffering." In other words, when we hate someone or something, behind that, there is always anger toward and fear from them, and behind anger, there is always fear. And fear, anger and hate are leading to suffering. Especially the fear of loss, that Yoda sensed Anakin in Episode I.
It's important to notice that although it's not spelled out directly until the Clone Wars, in Star Wars, "evil" is not a characteristic that some beings just are, and it's not a wicked, dark, fully Evil and malicious entity that tries to seduce and corrupt fallible human beings. Rather, it's actions, and effects of those actions, motivated by the dark side of the human condition: "some in [our] existence calls [it] evil, otherwise known as fear."
TRAINING THE MIND - LIVING MINDFULLY
"Be mindful of your feelings" and "thoughts", the development of the "most serious mind" are important parts of Jedi practice. Mindfulness is the simple act of paying attention and noticing and being present in whatever you’re doing. When you are being actively mindful, you are diligently aware, mindful, and attentive, you become aware of the world around you, the effects that you have on others around you, as well as your thoughts, feelings, emotions, behaviors, movements, and their effects on you. In other words, mindfulness is the awareness that arises through paying attention, on purpose, in the present moment, non-judgmentally.
This is when the mind is "calm, at peace, passive", so one can "know the good side [of the Force] from the bad", that is to be able to see things as they are, not just as they appear to be in the light of our heated emotions. Thus, it's possible to be like Master Yoda: "Part of me you are, yes. But power over me you have not." he says firmly to the reflection of his own "evil." "Through patience and training, it is I who control you. Control over me you have not. My dark side you are. Reject you I do." Then, one can respond with spacious clarity, purpose, firmness, and compassion.
LETTING GO OF POSSESSION AND ATTACHMENT
Everything we can think of - all things and beings - is changing, constantly moving through our lives, and we ourselves, our very existence changes, life itself is moving through us, as we come into this world, and, ultimately, leave it. As Shmi Skywalker explained, "you can't stop change any more than you can stop the suns from setting." Thus, attachment - love or liking for someone or something, infused with resistance to lose, and the feeling that we would be unhappy without them, the desire to hold on to things - should be ceased, for it's forever walking hand in hand with the fear of loss. Attachment has the "I" in the focus; "Others" are the sources of happiness, fulfillment, satisfaction, which are possessable.
"Train yourself to let go everything you afraid to lose" is training ourselves to see through the inevitable cycle of life and loss, and to gain awareness of the impermanent, transient nature of all things and beings, so we won't grasp, grab, or cling or hold on to transient things through our desire to stay in our lives and not to change.
LIVING ON COMPASSION: THE JOY OF BEING A JEDI
Pleasure is one kind of happiness, driven from the fact that there is something in your life that brings you enjoyment. Like a sunset, a great meal, a great music, great sex, or good weather, a good book, or the enjoyment of seeing your children growing up. And there is also the pleasure of having a loving, kind, warm person in your life. There is the pleasure of having enough to eat, a place to live, having medical care, clothes to wear, having education. So, pleasure is happiness at the sensual, physical, material level. Pleasure is great. However, we must be aware of the fact that our attachments are formed to pleasures, to the sources of pleasure, and accept that pleasure, just like its resources, are temporary, thus, our happiness based on them is short-lived. Otherwise, we end up in a cycle of greed: we want, we get, while being afraid of not getting, and when we have, we're afraid of losing, with anger, hate, aggression, bitterness thriving on our fear, robbing us from happiness.
On the other hand, there is another form of happiness, that is joy: satisfaction, happiness arising on the mental level. This mental joy, contrary to pleasure, sustains itself, thus, it's everlasting. This is the merit of compassion: genuine love and affection for others. By definition, compassion means to suffer with, to experience with, to feel with another person - a sense of oneness, innate connectedness with other. There is a sense of being parts of each other: just like when you hurt your finger, and you don’t think, "Oh, my finger is hurt, maybe I should help it", but rather, there is an instant and intuitive, natural response to it, the individual’s quest for happiness and to avoid suffering is completed by and merged with the happiness and the freedom from suffering of the other. If you're filled with negative judgment, anger, hate, fear from others, then you will feel separate from others, and you will feel lonely, even in the middle of a crowd. If you have an open heart, if you have compassion, you will never feel lonely, even if you are alone. Genuine, selfless concern for other's well-being, cultivating close, warm hearted feelings are putting the mind at ease, creating the peace of mind, and the more we care about other's well-being, the greater our own sense of well-being becomes.
And regardless what view we might hold about what will happen to us after we die, if we have compassionate love for our loved ones, compassion will defeat death. Regardless how we think about an "afterlife" - nirvana, going to heaven, being reborn, or, if we are materialists, dispersing and becoming other things in the universe, or becoming one with the Force - with compassion, no matter where or what our loved ones are or become, our love for them will never cease, nor a sense of oneness with them, nor our happiness.
As long as you have compassion, you won't be afraid.
MONASTIC LIFESTYLE AND GROWING UP IN A TEMPLE
Living in a temple, not pursuing romantic or sexual relationships, as well as being a member of a monastic order are not requirements to follow the philosophy I outlined above. At this point, we must take the fact, the Jedi Knights were designed to be mythological heroes in George Lucas' Star Wars, into account. As Lucas says, the Jedi were "designed to be a Buddhist monk" - Buddhist monasticism is about focusing entirely on spiritual development on the Buddhist path, to cultivate mental happiness and wisdom about the nature of reality. By doing so, one preserves the spiritual tradition by living it and studying it, as well as teaching it to others. Monastic living is not for everyone, nor it's a necessity, but it's very useful to avoid getting attached to pleasures and getting distracted from the goal.
A Jedi Knight leads a monastic lifestyle for practical reasons - ideas, such as being separated from worldly pleasures to focus on loving God or to seek God's approval, or considering pleasures sinful from which the body must be pure, are not playing any role here. The reason why younglings are leaving their homes, families, is to start their Jedi training as early as possible: to cultivate insight into the impermanent nature of reality, to train their mind to not to base their happiness on pleasures, to cultivate compassion. As George Lucas expressed, a Jedi Knight must raise above of average human tragedy and overcome the flaws that we all carry in ourselves and making us humans. But he always emphasized, this cannot happen without training and diligence, just like in real life, and in the real life, it's most often a life-long quest. The other part of the training is learning how to use the Force flowing within and around them.
The Jedi Knights are monk-warriors, committed themselves to guide the galaxy, to protect and preserve peace and justice in the universe. As George Lucas explained, the Jedi Knights "were never designed to be a superhero or anything like that. They were designed to be a Buddhist monk, who happened to be a very good warrior. And they became the peacekeepers of the human world." They aren't policemen, soldiers - they are "monks first, and they try to convince people to get along." They're "ultimate father figures" and "intergalactic therapists" and "warrior-monks who keep peace in the universe without resorting to violence." When they have to use violence, they do, but they're diplomats on the highest level.
A JEDI IS ABOUT BEING, NOT BELIEVING
If we define religion as a philosophy that posits an ultimate reality, providing a path to experience that ultimate reality, and the potential for personal transformation, then, yes, the Jedi Order is a religious institution, and Jedi philosophy is a religion. However, if we define religion as faith, unquestioning acceptance of doctrines that are laid down by an authority as incontrovertibly true, receiving revelations from a deity or a spiritual reality, involving worship, rituals, clergy and prayers, and the aspiration to build a connection with a deity, then, a Jedi Knight and the Jedi Order is not religious at all - the Jedi way is a relationship to self, to others and reality.