My dear friend: These varied traditions do appear to be quite different from one another, don't they? Your question is most timely, since so much is going on in the world which either seems to draw from, or be dependent upon one or the other of these religious traditions. To understand the concept of this "Oneness," you must begin to view such matters rather as realms of experiencing upon this physical plane. In other words, rather than seeing each tradition as something separate from all others and unique unto itself (even though most will argue that this is the case), we need to begin viewing from a larger perspective. If we can look from a vaster point of view, then understanding and becoming a part of this Oneness is neither so difficult nor strange as it may seem at first glance.

Think about a cherry pie, for example. When you are served a piece, you probably recognize it is not like any other piece cut from the same pie. You can easily see that one piece may have more cherries than other pieces, or perhaps fewer cherries. One piece may be tarter or sweeter than the piece which was positioned right next to it. Of course, many people do not have their tasting capacities so finely honed as to detect the difference; but in truth, there can be no two pieces exactly alike. The differences become more exaggerated if we have three pies, all appearing identical, and all made by the same person at the same time. Yet, from all the pieces cut out of these pies, no two will be exactly alike. Such might lead one to say that these pieces of pies are not the same, yet clearly, they are not different either. In considering thus, we begin to create a working definition of "Oneness."

Many experiences, relationships, encounters, creations, etc. are today viewed only from the perspective of their differing qualities. Indeed, one can make a case for this, for it does facilitate one kind of logical understanding that works in the modern world. There is, however, another kind of seeing that also works in the overall understanding of what is - although it may not be as popular in the current era. This other way of seeing depends on the ability to see things in terms of their likeness as opposed to their differences.

Now, many will believe that so seeing somehow dilutes uniqueness and/or originality, but such is not the case at all. For example: when you consider a dog, a tree, and a person, they all appear quite different - at least in form. Yet considering form is only one way of looking at living things. Another way is to view the life force, or creative impulse, which, while identical in all, manifests quite differently form to form. Every living thing shares qualities and function with all other living things; and these qualities and functions are undeniable. For example: all living things move; all living things breathe; all living things take in food and release waste products; all living things have the capacity to perpetuate their own species, etc., etc., etc. Seen from this perspective, we can say that living things, while form to form are not the same, seen at a vaster level are also not different. The life force which drives each and every living thing comes from the same Source, generates the same requirements to stay alive (although these do appear different from one form to another), and eventually leaves all forms when the appropriate time arrives.

If we look closely at all the religious traditions you mention in your question, we can see that all have many things in common. All seek to elevate the ones who follow a given tradition, and all do so by seeking to further educate the mind of their followers. Some focus on "salvation," others on "liberation." Who can really say that these two notions are divergent? One aspires to reach "heaven," another aspires to reach "nirvana." One tradition seeks to wipe out "sin," another "ignorance." While these two words are often used in contexts that would appear to demonstrate a chasm betwixt the two definitions, viewing both from a vaster perspective reveals a greater truth. Indeed, without ignorance, how can there be sin?

If we investigate even more deeply, we will discover a number of similarities in purpose, differences in doctrine notwithstanding. All these traditions teach that it is better to create one's life from a position of love than from greed, hatred or envy (to mention only a few). All hold that the individual can change, given s/he applies the teachings of the tradition. All ask their aspirants to raise themselves from degraded habits, striving to live as would a divine being. All teach against certain activities which are deemed inappropriate to all: killing, stealing, lying, coveting, speaking ill of others, being calloused and uncaring for other human beings, etc., etc. All teach that one is better to have received the teachings of the traditions than not to receive them. All seek to increase the happiness and abundance of their respective followers. And, all promise some form of benefit from practicing their respective teachings.

Simply stated, you could say all are merely different pieces of Earth's great "spiritual pie." (Without intending any form of glibness, or minimizing the contributions of any or all of these great traditions, the pie analogy is here offered as purely instructional. May it be a means for seeing connections among pieces which may appear quite different.) It is important to recognize that throughout a life stream, one will likely spend numbers of lifetimes in each of these traditions; attempting, in effect, to become completely balanced in the full spiritual spectrum of Earth. Since all the great traditions have great Teachers as originators, one can surely learn much from each. Thus, one learns to balance and open the head center in some traditions; to balance and open the heart center in others, and to balance and open the belly center in still others. Indeed, it is good to make use of the wisdom of all traditions, separating each from the cultural trappings when possible.

Always remember that life on Earth is basically an educational adventure. With such a wide spectrum of experiencing as exists on this planet, why miss any part of the whole by becoming too caught up in a single perspective? Live, learn, and love with abundance! Take joy in all ways of seeing - recognizing that each perspective contributes to the whole. Indeed, you can have a piece of the pie; but if you really want it, you can have the whole pie as well.