In the poem "Crossing the Bar" by Alfred, Lord Tennyson, death is compared to a ship putting out to sea. Often at the mouth of a harbor or a river, the movement of water by the tide or other means causes a sandbar to accumulate. To the poet, this sandbar marks the transition between the safe, shallow waters of life and the boundless deep ocean of death. In the first stanza, the narrator asks that there should be "no moaning of the bar" when he goes out to sea. This refers to the sound the wind might make when the sandbar is exposed and it would be dangerous to travel over it. Instead, the narrator hopes for a safe, smooth transition when he puts "out to sea." In other words, he hopes for a calm and easy death.
In the second stanza, the narrator again emphasizes his hope for an easy passage from life to death, and he uses the tide as a metaphor. He hopes that it will be "too full for sound and foam." This refers to a movement of the tide that would be so full that it would not foam against the sandbar but instead be smooth enough as to seem "asleep," or not moving at all.
In the third stanza, "twilight and evening bell" refer to the onset of old age, and "the dark" refers to death. When the narrator dies, he sees it as a natural occurrence, and so he hopes that his farewell from life will not be sad.
In the fourth stanza, the poet gives his main reason for the calm acceptance of death. Once he crosses the bar, he expects to "see my Pilot face to face." This is a reference to having a face-to-face encounter with God after death. The narrator's confidence in this meeting causes him to accept death calmly, and by inference he exhorts us to do the same.