Philosophy is a subject which is trying to find a knowledge of a given subject to its utmost depth and detail. Of course, Philosophy has a limit. In Indian Philosophy, one is trying to find the knowledge related to human existence rather than any other knowledge. A similar quest has been done in other traditions including some religious traditions.
Religion is a subject which is trying to implement philosophical finding in actual practice, but depending on the environment or surround of a given section of society, depending on a given time frame, and depending on the limitations of the finding itself.
Of course Philosophy is not totally complete. Because, knowledge and its detail are infinite. However, Religion is always more limited than the Philosophy, because Religion is even more limited by limited implementation of the Philosophy.
Religion is a method to implement philosophy in a certain way. Thus, there will be lot of differences in various religions even for implementing the same truth. It is like different vessels to drink the same water, or it is like cooking the same grain in different ways making different dishes. But, whether one drinks water through a glass or through simply hands, one still gets the same effect of water for the biological body. Similarly, one shall reach the same truth if religions are implementing the truth, and not just the methodology.
When religions implement only methodology, they become fanatic and they feel all other methods are wrong or evil. Now, they start talking about untruth as truth, they start killing in the name of life, and rioting in the name of peace, and materialism in the name of spiritualism. And, they think religion as philosophy. Slowly, their knowledge is replaced by ignorance.
asato ma sad gamaya, tamaso ma jyotir gamaya, mrutyor ma amrutam gamaya…. Upanishads..
Lead me from untruth to truth, from ignorance to knowledge, and from death to immortality. ..