As the Pequod's crew works on the whale, another Nantucket whaling ship, named the Jeroboam, approaches. Its captain and some of the crew come nearby in an open boat. There is a "malignant epidemic" aboard the Jeroboam so the captain refuses to board Ahab's vessel. In addition, the stranger ship seems almost under the control of a raving Shaker prophet who thinks he is the archangel Gabriel. Gabriel believes that Moby Dick is the incarnation of the Shaker God and warns against confronting the White Whale.
The meeting with the Jeroboam heightens the ominous atmosphere surrounding the Pequod's quest. It is important to note that the biblical Jeroboam (1 Kings 11-14) suffers because of obstinacy and his failure to heed the warnings of a prophet. So, too, the vessel Jeroboam suffers when it ignores Gabriel, mad though this Gabriel may be. (The biblical Gabriel [Daniel 8:16; Luke 1:26] is a herald of good news, including, to Mary, the revelation that she will be the mother of Christ.)
In the novel, Gabriel warns against confronting Moby Dick who is, he claims, the Shaker God; this adds to the mystery of what Moby Dick really is. When the Jeroboam's crew did pursue the White Whale, one of its mates, Harry Macey, was killed in a mysterious way as the whale's sweeping tail hit only him, leaving the open boat and the rest of its crew untouched. Gabriel also claims to have caused the "plague" aboard ship and to be the only source of its cure.
As the Jeroboam and the Pequod attempt their awkward, quarantined gam, Ahab remembers that he has a letter for the deceased Macey and tries to pass it to the other ship's captain. Gabriel grabs the letter and casts it back aboard the Pequod, crying, "Nay, keep it thyself, . . . thou art soon going that way," meaning that Ahab will soon join Macey at the bottom of the sea.
Shakers here, short for Shaking Quakers, a sect so named because of trembling caused by emotional stress or euphoria of devotions.
bilious bad-tempered, cross.