What are the similarities and differences in Rig, Yajur, Sama and Atharvana Vedas? To my knowledge maximum come from Yajur Veda. Next comes Rig. Third place for Sama and the last for Atharvana. Do the four vedas teach the same thing? If so for example why there is difference in ceremony procedure among vaishnavite, Saivite and Rayars [disciples of Raghavendra swamy] although they come from yajur? Any Vedic reference for this.
In order to understand similarities and difference in four Vedas, I think it is necessary/recommended to know why and how Veda is divided into four Vedas. Following answer will help you to know & understand it according to the relation of Veda and Yajna.
Teaching and studying Vedas are not simple task even during the end of Dwapara Yuga. Considering the incapability and short life-period of man, Sri Krishna Dvaipayana Vedavyasa divided Veda into 4 parts according to the usage of Veda in Yajna(यज्ञ) § which are known as Rigveda, Yajurveda, Samaveda and Atharva Veda today.
The prime goal of Veda is to give spiritual knowledge so-that one can understand the cause for bondage of Samsara and can attain liberation from it.
There is both topics/subjects i.e., Karmakanda(कर्मकाण्ड) and Jnanakanda(ज्ञानकाण्ड) represented comprehensively/overall in Veda. Karmakanda is the preliminary part of Veda which is bigger/more comparatively to Jnanakanda. There is an comprehensive interpretation/discussion of Vidhi-Nishedh etc. in karmakanda part. There is prime use of this Karmakanda part in Yajnanushthan (Yajna-ritual/rite/ceremony). One who has rights of doing Yajna from Yajmana is called Ritvij(ऋत्विज ) or Ritvik(ऋत्विक) i.e sacrificer. There are four class/groups/types of Ritvij which are:
Above mentioned 4 types/class of Rutvij accomplish whole Yajna doing their tasks.
According to the collection/compilation as per the use of mantra for above mentioned four group/class, Veda become four as follows:
Yajurveda - Collection of mantras useful for Adhvaryu. There are majority Gadya types of mantras.
Sama Veda - Collection of mantras useful for Udgatru. There is only specific mantras of Gaayan type. Majority of these mantras are available from Rig Veda.
Atharva Veda - Collection of mantras useful for Brahman. The job/task of Brahman class is to observe and supervise work of Yajna, to give instructions/indications periodically, to atonement in case any mistake done by Rutvij or Yajman and to overcome/remove any fault in Yajna. The naming of Atharva is according to predicable theme of it and also according to Atharva Rishi as this Veda is mostly disseminated by him.
Some of the mantras are found in two or three Vedas uniformly. The reason for this is that the division of Veda is done according to usefulness of mantra for Rutvij for Yajnanushthan. Thus the presence of same mantra in other Veda in different occasion for the different class of Rutvij is natural, even though the same mantra is found in other Veda in another occasion for another Rutvij.
Reference/Source : वैदिक वाङ्मय का शास्त्रीय स्वरूप
§ According to Madhusudan Sarasvati - Prasthana Bheda:
सः च प्रयोगत्रयेण यज्ञनिर्वाहार्थमृग्यजुःसामभेदेन भिन्नः । तत्र होत्रप्रयोग ऋग्वेदेन, आध्वर्यवप्रयोगो यजुर्वेदेन, औद्गात्रप्रयोगः सामवेदेन, ब्राह्मयाजमानप्रयोगौ त्वत्रैवान्तर्भूतौ । अथर्ववेदस्तु यज्ञानुपयुक्तः शान्तिपौष्टिकाभिचारादिकर्मप्रतिपादकत्वेनात्यन्तविलक्षण एव । एवं प्रवचनभेदात्प्रतिवेदं भिन्ना भूयस्यः शाखाः । एवं च कर्मकाण्डे व्यापारभेदेऽपि सर्वासां वेदशाखानामेकरूपत्वमेव ब्रह्मकाण्डे । इति चतुर्णां वेदानां प्रयोजनभेदेन भेद उक्तः ।
The Vedas are different for three kinds of application as Rg, yajus and sAma, for the purpose of performance of sacrifices. The hota uses Rgveda, the adhvaryu yajurveda and the udgAta sAmaveda. The brahmA and the yajamAna also use the same Vedas. The atharvaveda is not used in yajnas. It is quite different, since it deals with the performance of shanti, pouShTika, abhicAra and other such karma. Each veda has many different branches with differences in the texts. Thus, though in karmakANDa, there are different applications, in brahmakANDa all the branches of the Vedas are of the same nature. Thus the differences among the four Vedas due to different purposes have been stated.