SB 4.3.12

Here Lord Siva is addressed as abhava, which means one who is never born, although generally he is known as bhava, one who is born. Actually Rudra, Lord Siva, is born from the eyes of Brahma, who is called svayambhuva because he is not born of any human being or material creature but is born directly from the lotus flower which grows from the abdomen of Visnu. When Lord Siva is addressed here as abhava, this may be taken to mean one who has never felt material miseries. Sati wanted to impress upon her husband that even those who were not related to her father were also going, to say nothing of herself, who was intimately related with him. Lord Siva is addressed here as blue-throated. Lord Siva drank an ocean of poison and kept it in his throat, not swallowing it or allowing it to go down to his stomach, and thus his throat became blue. Since then he has been known as nilakantha, or blue throated. The reason that Lord Siva drank an ocean of poison was for others' benefit. When the ocean was churned by the demigods and the demons, the churning at first produced poison, so because the poisonous ocean might have affected others who were not so advanced, Lord Siva drank all the ocean water. In other words, he could drink such a great amount of poison for others' benefit, and now, since his wife was personally requesting him to go to her father's house, even if he did not wish to give that permission, he should do so out of his great kindness.