Lord Balarama

From Srimad Bhagvatam, just like one candle lights another candle, Lord Krsna's first expansion is Lord Balarama. Lord Balarama is non-different from Lord Krsna, He also possesses 64 qualities like Lord Krsna the only difference is He is white in color in comparison to Lord Krsna's blackish complexion. So, there is no difference. He is called Balarama as He has tremendous amount of Bala - strength (spiritual strength), without approaching Lord Balarama we cannot approach Lord Krsna. Lord Balarama is the original spiritual master and Guru is a direct representation of Lord Balarama.
In their earthly pastimes in treta yuga, Lord Balarama is Laxmana while Lord Krsna is Lord Rama. In that pastimes, Lord Laxmana is unhappy few times while following the orders of Lord Rama but was forced to follow since He was the younger brother like when He had to assist Mother Sita for Agni-pariksha which He was completely against to. So, He resolved that He will never appear as a younger brother. So, in Krsna-lila and than Gaura-lila, He appears as a elder brother of Lord Krsna and Lord Gauranga.

In Krsna-lila, Lord Balarama was the seventh son of Mother Devaki after her six sons were killed by Kamsa, Lord Ananta manifested within the womb of Mother Devaki. Mother Devaki felt pleased but immediately felt sorrowful that Kamsa will kill the Supreme Personality of Godhead. So, she prayed humbly to the Supreme Personality of Godhead, Lord Krsna. Lord Krsna requested His energy Yoga-maya to transfer the baby from the womb of Mother Devaki to the womb of Mother Rohini who was also pregnant, and as a result Lord Balarama is also called Sankarshana.
Mother Devaki is Bhakti Devi, personification of Devotional service. She delivers six son's who are killed by Kamsa, which personifies killing of six natures of a living entity lust, anger, greed, illusion, pride, and envy. For the manifestation of Supreme Personality of Godhead within our heart this six bad qualities needs to be destroyed