SB 10.46.1
sri-suka uvaca
vrsninam pravaro mantri
krsnasya dayitah sakha
sisyo brhaspateh saksad
uddhavo buddhi-sattamah
Translation:
Sukadeva Gosvami said: The supremely intelligent Uddhava was the best counselor of the Vrsni dynasty, a beloved friend of Lord Sri Krsna and a direct disciple of Brhaspati.
Purport:
The acaryas give various reasons why Lord Krsna sent Uddhava to Vrndavana. The Lord had promised the residents of Vrndavana: ayasye, “I shall return.” (Bhag. 10.39.35) Also, in the previous chapter Lord Krsna promised Nanda Maharaja: drastum esyamah, “We will come back to see you and mother Yasoda.” (Bhag. 10.45.23) At the same time, the Lord could not break His promise to Sri Vasudeva and mother Devaki to finally spend some time with them after they had suffered for so many years. Therefore, the Lord decided to send His intimate representative to Vrndavana in His place.
The question may be asked, Why did Krsna not invite Nanda and Yasoda to visit Him in Mathura? According to Srila Jiva Gosvami, for the Lord to have exchanged loving feelings with Nanda and Yasoda in the same place and at the same time that He was exchanging them with Vasudeva and Devaki would have created an awkward situation in the Lord’s pastimes. Thus Krsna did not invite Nanda and Yasoda to stay with Him in Mathura. The residents of Vrndavana had their own way of understanding Krsna, and their feelings could not have been appropriately expressed on a regular basis in the kingly atmosphere of Mathura.
Sri Uddhava is described in this verse as buddhi-sattamah, “the most intelligent,” and thus he could expertly pacify the residents of Vrndavana, who were feeling such intense separation from Lord Krsna. Then, upon his return to Mathura, Uddhava would describe to all the members of the Vrsni dynasty the extraordinary pure love he had seen in Vrndavana. Indeed, the love the cowherd men and gopis felt for Krsna was far beyond anything the Lord’s other devotees had ever experienced, and by hearing about that love all the Lord’s devotees would increase their faith and devotion.
As stated in the Third Canto by the Lord Himself, noddhavo ’nv api man-nyunah: “Uddhava is not even slightly different from Me.” Resembling Krsna so much, Uddhava was the perfect person to carry out the Lord’s mission in Vrndavana. In fact, Sri Hari-vamsa states that Uddhava is the son of Vasudeva’s brother Devabhaga: uddhavo devabhagasya maha-bhagah suto ’bhavat. In other words, he is a cousin-brother of Sri Krsna’s.