One of the concepts that some people have a hard time grasping is the idea of “oneness”. I.e., the idea that in reality we are all really one person or entity. Ironically, people who are strongly identified with their egos seem to be more inclined to remind others that we are all one. This isn’t a judgement; it’s a way of pointing out that we should be careful about what we are doing with the truths that we learn and believe in. In general, truths are for the purpose of spiritual development, but they can easily become traps for the ego as well.
In this particular case, the ego can take this expression as a way of exclaiming that “I know that we are all one, which makes me spiritually superior to those that don’t”. Or the self-victimizing: “I know we are all one, so why can’t I remember this fact when dealing with others?”. Note that the expression “we are all one” includes the word “we”. So an a certain level, this concept could keep a person trapped in dualistic thinking. Depending on how the non-dualistic world is perceived, there isn’t necessarily such thing as “we”: there is only the “one”.
It is helpful to keep in mind that the Truth can never be adequately described in words. I.e., once you try to explain any concept, including that of duality and oneness, words will always fall short. So it’s important to not get caught up on spoken truths and “spiritual cliches”, as this can lead to spiritual stagnation.
Non-attachment to Spiritual Teachings
Some spiritual teachers are good about emphasizing the fact that nothing that they say is actually the Truth. Instead, they are clear that what they are doing is using language as a tool in order to bring their students closer to the Truth. In Buddhism, there is the saying: “The finger pointing at the moon is not the moon”. In other words: spiritual teachings in themselves are not the Truth, they merely point at the Truth.
Another helpful Buddhist concept states that in order to achieve full realization, all attachment must ultimately be abandoned. This includes attachment to all spiritual concepts.
This does not mean that one should not believe in anything. Spiritual teachings are useful as “guiding principles” for spiritual development. You can think of spiritual teachings as rungs on a ladder: in order to continue to develop, you must continually release one truth in order to “grasp” another. The key here is that in order for you to reach the ultimate truth, you must continually advance from one spiritual level to another. If you become attached to any one level or lesson, you will get stuck.
At some point in your spiritual development, you may have the opportunity of actually experiencing a certain level of the Truth; i.e. the experience of “oneness”. This is known as the “enlightenment” experience in Buddhist philosophy, and is sometimes referred to as the experience of “grace” in Christianity. With such a realization, it will then be possible to fully “know” the Truth, and the teachings that were learned to discover this Truth will no longer be necessary.