Baptism is important because it is a sign; it's as though when you go down below the water and come out, you are mimicking this journey of Jesus. But early church tradition also linked baptism to a denunciation of the dark powers, in the baptismal formulas. Because their idea was Jesus goes down there, he preaches to the spirits in prison, and Peter hints that those spirits are not the dead humans. They are the Watchers from the book of Enoch. Check it out!