Before I go into these reasons I should note that while the Truth is common to all human experience and several other spiritual traditions exist, the tradition that I am most familiar with is the Vedic tradition called sanAtana dharma. There are a few good reasons for restating that which has already been already said so well by those who went before. The first reason is that the original message in the Vedic tradition was orally transmitted and subsequently written down a long time ago in Sanskrit, a language that most people are not familiar with. To complicate matters, the subject matter is esoteric and requires experiential interpretation to have any real value. Only through direct experience of the concepts described in the Yoga sUtras and Upanishads can their true meaning be known. This requires sAdhanA. Mere discussion of the words that describe the concepts will not take the seeker to the goal. But the words are important insofar as they light up the path. This is why studying with a guru (who by definition not only had direct experience, but was the living embodiment of the Truth) was emphasized in the Vedic tradition. The same words can be misinterpreted by someone who does not have that experience. So even if someone has access to the exact word meanings of the texts, ultimately it is only those interpretations of those words informed by direct experience that are most useful for the aspirant.
Even so far as obtaining the exact word meanings of the texts, several difficulties present themselves. The original texts are in Sanskrit, a language that many are not familiar with. I highly recommend sincere seekers to start learning Sanskrit, at least at the elementary level. Even for one who knows Sanskrit, there are challenges. While there are many commentaries on the ancient texts, relatively few give the original text in DevanAgarI with breakup of euphonic combinations (sandhi), word-for-word translation and simple translation (saralArth), followed by the interpreted meaning (bhAvArth). This is the classical way of studying Sanskrit texts. As a result, aspirants often do not even have access to the exact word meanings of the texts, let alone their interpreted meaning.
Sanskrit is a language in which the same word can have different meanings, and the word’s meaning changes with time (e.g., between Vedic and Classical periods) and subject matter (Yoga sUtras, sAmkhya to VedAnta) of the text. Especially in the areas of spiritual experience, philosophy and religion, there are many Sanskrit words that do not have a direct English counterpart. Many of these meanings are learned intuitively by growing up immersed in the Hindu tradition of religion and spirituality. So there can sometimes be a difference in intuitively knowing the meaning of a Sanskrit word through growing up in the cultural context in which it is used often with different nuance and shades of meaning, and learning the translated meaning second-hand through another language. I say all this from the perspective of one who grew up in an orthodox Brahmin family in India and learnt Sanskrit in the native tradition and then subsequently studied Sanskrit in the Western world, thereby gaining an appreciation for the rigor and precision of that approach as well. Both the so-called native and Occidental approaches have their merits and demerits. The skillful sAdhaka will learn to use both to maximum benefit.
I felt inspired to write these articles because I hope the understanding I have gained may help others. Although I have been reading original texts in Sanskrit for the last twenty years, it is only after gaining direct experience of the subject matter through my own sAdhanA that I now feel competent to write about these matters. I believe there is value in revealing the beautiful interplay of concepts from Yoga, VedAnta and Tantra that together help in constructing a coherent meaning of man's internal states and the external world. Much has been lost by presenting these as bewilderingly different approaches, when in fact they all lead to the same Unity.
Finally, most of the practical approaches to sAdhanA are written by SwAmis or renunciates. Of these I have found the works of SwAmi RAma and SwAmi JnAneshwara BhArati to be most useful. Swami JnAneshwara BhArati has a website http://www.swamij.com that is simply indispensable for the sincere seeker. I frequently refer the reader to his articles because they are so well-written and useful. I write from the perspective of a householder with work and family duties. My intention is to give the aspirant some additional insight from that perspective. It is also possible that even the same message recast through the lens of my personal experience may help someone who is facing a specific difficulty on the path. The intent is that these contributions will complement, and hopefully not duplicate, what SwAmi JnAneshwara BhArati and SwAmi RAma have already explained so thoroughly. I hope these articles will inspire sincere sAdhakas (spiritual aspirants) to continue to tread the path. Whatever resonates with you in these articles is probably because of the universality of the message, and whatever does not appeal to you reflects each of our personal limitations. There are many genuine paths, and each of them is equally valid because they all lead back to the same source. So take with you as much or as little of what you read according to your taste, and I hope you find some of it useful.
Om tat sat, brahmArpaNam astu