Vyasa collected a subset of Mantras at the end of the last Yuga or Era. Certainly a larger set of Mantras was in vogue earlier. Vyasa created four compilations from the subset. These compilations are today known as the four Vedas, namely, the Rig, Yajur, Sama and Atharva. Several mantras are common between the Rig, Yajur and Sama Veda compilations. Almost every Sama Veda mantra is also in the Rig Veda compilation. However, not all mantras of the Rig Veda are in the Yajur Veda compilation. Because of this, Yajur Veda contains mantras which are not in the Rig Veda. What is the reason for the overlap of Mantras?
Overlap of Mantras in the Rig, Yajur, Sama Vedas
The tradition of Yagnas has continued through the ages. Secondly, the first step in the Yagna involves inviting appropriate Devas to the Yagna. Thirdly, Rig mantras alone can invoke the energies of Devas. Offerings to Devas is the second step in a Yagna. This is an important aspect which connects the material existence to the subtle. However, Yajur Veda priests must sanctify these offerings. They do this by using mantras. Subsequently, they place the purified offerings to the Yagna. Additional chanting the mantras accompany the act of offering to the Devas.
The third step in a Yagna is interesting. Sama Veda priests seek the blessings from the Devas. This happens towards the end with the chanting of Sama Veda mantras. Saman chants touch the heart of Devas. Secondly, they establish a feeling level connection between the human plane and the plane of the Devas. As a result, Devas grant the fruits of the Yagna to everyone.
Normally, a mantra is addressed either to a single Deva or a group of Devas. A common mantra can be address to address the same Deva in the above three steps. However, the intonations differ. This difference identifies the purpose for which the Mantra is being chanted. Musical notes flourish in Sama Veda chants. Certainly, Sama Veda is the precursor to classical Indian music. Similarly, the style of chanting is distinct for the Rig and Yajur Vedas. A casual listener can also begin to distinguish this style difference in a short time. The following is a beautiful rendering of a few popular mantras in the Rig and Yajur style of chanting. From this one can get a better sense about the style differences despite the overlap of mantras.