Narada said- You have narrated about the marriage of several damsels with Krishna but the mystery about the Syamantaka remain unfolded. O virtuous, one I have not heard about it. You kindly tell me.
Narayana said- In the earlier times on the fourth moon day of the Bhadrapada, the moon abducted Tara and freed her on the fourth moon day of Ashvina. Bruhaspati then accepted her. The chaste lady felt shameful because of her conception Bruhaspati denounced her and Tara in anger pronounced a curse on the moon getting filled with shame and anger.
Tara said- You would earn the blemish because of my curse. Whosoever you look at you on the fourth moon day of Bhadrapada, he would also earn blemish.
On hearing this, the moon went to the Narayana-sarovara and performing tapas there he was free from the sin.
Finding the moon having become so lean and thin, the compassionate Narayana mercifully told him.
Vishnu said- O moon you will be freed from the blemish for all the times. Only such a person would earn a blemish, who would look at you on the fourth moon day of Bhadrapada quite willingly. The blemish of moon would be transferred to such a person and he would earn a blemish.
Lord Hari announced with the clapping of the hands that on the fourth day of the moon either in the bright or dark fortnight, the moon should not be witnessed.
He also followed, the declaration about the moon for himself and because of that he earned a blemish on the fourth day of the night in Bhadrapada. Now I shall narrate to your way in which he earned the blemish. The lord was freed from the blemish to educate the people.
Satrajita a devotee of Surya performed tapas at Pushkara-tirtha and achieved Syamantaka gem from Surya.
The Syamantaka gem produce eight bharas of gold daily. Lord Vishnu was established in that gem.
Satrajita got ready to present the said gem with devotion to Satyabhama as a dowry. Moved with the evil time the wicked Prasena stopped him from doing so and stealing the gem he went to the auspicious place of Varanasi.
But on the way a very strong lion killed him and took away the gem with the cord and wore it round his neck. The lion was none else than then the son of the king of Kalinga, who had been facing the curse of that Brahmana and had taken to the form of an animal. The same lion was killed by a very strong beer named Jambavan and carrying the gem with him, he reverted to his abode.
On the other hand, people in Dvaraka started saying that the gem had been stolen by Krishna and it was difficult to find out the way by which he stole away the gem.
On hearing this in order to wash out the blemish, lord Krishna moved in the forest on the path bearing the foot-prints of the thief.
Finding Prasena having been dead, he was grieved. Then he found the lion but finding, him without the gem, Madhava felt disinterested.
Thereafter, the all-knowledgeable Krishna, because of his divine power came to know of everything and went to the abode of the beer, he found a child sleeping in the lap of the mid-wife.
The mid-wife getting filled with compassion was talking to the child, "you have this gem known by the name of Syamantaka which belongs to you,".
The lion killed Prasena and Jambavan killed the lion. O prince don’t cry, this gem belongs to you.
The one who recites this stotra, composed by the mid-wife and then drinks the water, he is relieved of the blemish of witnessing the moon on the prohibited day.
Such of the wicked person who denounces the Vedas and willingly witnesses the moon on the prohibited day, he surely earns the blemish.
On hearing the words of the midwife Krishna took away the gem from the child. The enraged midwife went to the beer and spoke to him.
Jambavan than come there and started eulogising Krishna. Thereafter, he gave away his daughter Jambavati to him together with the divine gem in dowry.
Lord Krishna went to Dvaraka and showed the gem to Yadavas and was freed from the blemish.
O son, I have narrated to you the story of the Syamantaka gem with the hearing of which one is relieved of all the blemish.
I have narrated to you the beautiful story which I had heard from the mouth of Dharmaraja in earlier times, what else do you want to listen from me now.
Summary of chapter 122 of the Brahma Vaivarta Mahā Purana - Śrī Kṛshṇa Janana Khaṇḍa is as follows:
This soul-nourishing chapter details the immense spiritual merits earned by hearing or studying all four Khaṇḍas of the Brahma Vaivarta Purāṇa. Śrī Sūta Gosvāmī declared that a person who hears this grand scripture with faith achieves the merit of bathing in all sacred rivers, performing all Vedic sacrifices, donating the entire earth in charity, and liberating hundred generations of ancestors.