Why Guru mantra is given in right ear?

Question

In Hinduism, there is long and very common tradition of making a saint/sage or an enlightened person, one's Guru.

One of Guru's role is to be spiritual mentor to his/her disciple and ensure disciple’s spiritual growth.

During mantra diksha,which is giving of a mantra or an initiation by the guru.Diksa is given in a one-to-one ceremony, and typically includes the taking on of a serious spiritual discipline.

Typically, The guru whispers the mantra into the disciple’s right ear, along with instructions on how and when to chant it.

Now why right ear? There must be a reason for this as it is consciously and deliberately done and followed.

Are there any scriptures that explains the whole process of mantra diksha with specific details as to why Guru mantra is given in right ear?

Answer 1

It is not necessary that every time during DikshA, the Guru must speak the Mantra onto the disciple's right ear.

The rule, as to which ear, depends on the Varna of the disciple and the gender. The rules of DikshAs also can vary with SampradAyas, ParamparAs and Mantras themselves.

ViswaSAra Tantram, RAdhA Tantram etc , for example, mention speaking Mantra unto right ear (Daksha Karna)

And, i know about Mantras, which are to be spoken into the ears not for 3 times but 8 times.

From Vashishta Tantram (a Vaishnava scripture):

Tatah RishiAdisamyuktam Mantram Gururdakshina karne Trih SrAvayitvA VAma karne Sakrit SrAvayet.

........

Thereafter the Guru should speak the Mantra, along with Rishi, Devata and other Angas, 3 times in the disciple's right ear and 1 time in the left (vAma karne Sakrit).

From the Gautamiya Tantram (another Vaishnava Text):

Nyasa jalam tasya dehe Guruh samnyasya jatnatatah |
Daksha karne Vaden Mantram TrivAram PurnamAnasaha ||
Dakshe Iti DvijAtivishayam..

.......

The Guru should do Nyasas with care on the disciple's body and speak mantra into his right ear three times. This rule of speaking unto the right ear is only for the DvijAs.

When the disciple belongs to one of the Dvija Varnas then, the Mantra is spoken unto the right ear first for 3 times, thereafter 1 time it is spoken unto the left ear.. Now, this process is reversed when the disciple is a Sudra or a woman.

From Bhairavi Tantram (a ShAkta Tantra):

Daksha Karne Triso VidyAm EkorchArena ChocchAret |
Evam Vidhim DvijAtinAm Stri SudrAnancha VAmatah ||

.......

The Guru shall speak the mantra into the disciple's right ear 3 times and into his left ear 1 time. This is the rule for the Dvijas, for women and Sudras it's just the opposite i.e 3 times in the left ear and 1 time in the right.

The same repeats the Rudra YAmala Tantram (which is another ShAkta scripture):

Gurustu PrAngukhobhutva ShishyA Prachi Mukha Stithah |
TrivAram Dakshine Karne VAme chaiva TathA Sakrit ||
Viparitam Tato Geyam StreesudrAnancha VAmatah |

..........

Guru should face the east and the disciple the west direction. Guru should then speak the mantra into the disciple's right ear 3 times and left ear 1 time. For Sudras and women the process will be reversed.

And, besides the scriptures i have mentioned, there are plenty of other Tantras and Agamas, where such rules of DikshAs are detailed.

Answer 2

I think this is because it is commonly accepted that in the right ear, the various devas (gods) reside. For example, in the Devi Bhagavata Purana, Book 11, Chapter 3:

After sneezing, spitting, touching the lower lip with teeth, accidentally telling a lie, and talking with a very sinful man, he is to touch his right ear (where the several Devas reside). On the right ear of the Brāhmaṇas reside Fire, Water, the Vedas, the Moon, the Sun, and the Vāyu (wind).

And the Garuda Purana, Chapter 97:

A Brahmana need not rinse his mouth with water after an act of sneezing, sleeping, spitting, wearing an apparel, or lachrymation. It is enough to touch his right ear under the circumstance, since all the gods, such as Agni, etc., reside in the Scapha of that organ of a Brahmana.

Further, in his translation of the Kathasaritsagara, C. H. Tawney makes an interesting note on the rite of the sacred thread:

... The boy faces the sun, holding the thread by the thumb and little finger of each hand, in such a way that it passes in front of the three middle fingers. The left hand must be held higher than the right. The preceptor repeats a mantra, at the conclusion of which the boy slips the thread over his own head. He now receives a staff, varying in size and wood according to his caste...

... A series of questions and answers follows, concluding with the teaching of the most famous of all mantras, the gāyatrī. So sacred is the verse that both the boy and his guru are covered with a silk shawl, lest any sound be overheard. The right ear of the child into which the verse is repeated becomes holy for life after merely hearing it. It usually takes three days for the verse to be learned perfectly. The boy now offers nine pieces of wood dipped in clarified butter to the fire, with appropriate prayers to Agni, Sarasvatī, and the Sun.