After Ravana was killed Rama had to atone for the sin of killing a Brahmin. All the saints advised Rama to install Shiva-linga in order to be freed from this sin. Criticizing Guru, mother or father, negligence in performing the annual rites of parents, abortions, killing of cow are heinous sins. Installing a Shiva linga per the procedure specified in the scriptures is the most supreme way to redeem oneself from these sins.
Rama decided, ‘This is the most auspicious moment. Hence right now we should get a Shiva linga from Kashi and install it here.’ Hanuman alone could rush to Kashi at such unimaginable speeds and fetch the Linga. Hence Hanuman was given this task. ‘Hanuman, I never get an opportunity to repay you, but seem to be calling you for every trivial task. Please do me a favour by going to Kashi” requested Rama.
Hanuman replied, “It is my privilege that you seek my services. There is no dearth of attendants who are ready to serve you. Instead you still think of me and call me. Isn’t that my privilege? I am so fortunate.”
Hanuman rushed at the speed of wind and reached Kashi. However when he saw crores of Shiva-lingas he was in dilemma. Which Linga was he to carry back to Rameshwaram? What were the specifications for the linga to be installed? Should it be big or small? Should he select a white linga, a black linga or a narmada bana linga? hn despair He called out, “Rama, what am I to do now?”
He then prayed to Shiva, sought his guidance and rushed back. Scholars in Tamilnadu declare that with Shiva’s blessings Hanuman picked up four Shiva lingams i.e. 2 in his hands, one in the tail and one in the mouth. Scholars from other parts of India state that he brought 3 Shiva lingams of which the 2 held in the hands fell en-route due to the speed at which he was moving. There are many sacred pilgrim centres in India which contain the pieces of the lingams that fell from Hanuman’s hands as he was returning to Rameshwaram. Only the lingam held in his tail was intact when he reached.
Meanwhile the auspicious time for consecration of Shiva-linga was coming to an end hence Mother Seeta made a Shiva-linga with sand (saikata linga) which Rama consecrated. With this He washed away the sin called Brahma-hatya doṣa (sin incurred by killing a Brahmin).
When Hanuman arrived in Rameshwaram with the Shiva-linga in the tail he observed that another Shiva-linga was already installed. He grieved that he failed in accomplishing Rama’s task. Consoling him Rama said, “Hanuman, the Shiva-linga brought by you is very dear to me. I shall consecrate it near to the main linga. In future time period people who visit Rameshwaram will have to first have darshan of Hanumadīśwara Shiva-linga and only thereafter have darshan of the main Shiva-linga. Only then their trip will be rendered fruitful”.
Rama continued, “I will now tell you a great secret why I had to send you away during the consecration of the main Shiva-linga here. For the consecration of this Shiva-linga created by Mother Seeta, I had invoked praṇa (life-force). In other words, I had invoked Shiva himself! Had you been present, you would have entered and merged into that Lingam. You would have thought, ‘Rama is asking me to enter into the lingam. Why should I delay?’ With this thought you would have instantly entered the Lingam and remained in it permanently. So I had to send you away.
Hanuman you will stay with me as long as I live on earth. Thereafter you will still continue to remain on earth propagating devotion towards Rama. In the future period of time you will become Brahma. This is my sankalpa.”
From this it is evident that Hanuman is none other than Shiva!
— Shivaratri 2015