Vasudeva, who was to be the father of Krsna, is described here (in SB 10.1.36) as maha-bhaga, a very upright and sober personality, because although Kamsa was ready to kill Vasudeva's wife, Vasudeva remained sober and unagitated

Expressions researched:
"Vasudeva, who was to be the father of Kṛṣṇa, is described here as mahā-bhāga, a very upright and sober personality, because although Kaṁsa was ready to kill Vasudeva's wife, Vasudeva remained sober and unagitated"

Srimad-Bhagavatam

SB Canto 10.1 to 10.13

Vasudeva, who was to be the father of Kṛṣṇa, is described here as mahā-bhāga, a very upright and sober personality, because although Kaṁsa was ready to kill Vasudeva's wife, Vasudeva remained sober and unagitated. In a peaceful attitude, Vasudeva began to address Kaṁsa by putting forward reasonable arguments.

SB 10.1.36, Translation and Purport

Wanting to pacify Kaṁsa, who was so cruel and envious that he was shamelessly ready to kill his sister, the great soul Vasudeva, who was to be the father of Kṛṣṇa, spoke to him in the following words.

Vasudeva, who was to be the father of Kṛṣṇa, is described here as mahā-bhāga, a very upright and sober personality, because although Kaṁsa was ready to kill Vasudeva's wife, Vasudeva remained sober and unagitated. In a peaceful attitude, Vasudeva began to address Kaṁsa by putting forward reasonable arguments. Vasudeva was a great personality because he knew how to pacify a cruel person and how to forgive even the bitterest enemy. One who is fortunate is never caught, even by tigers or snakes.