The image of the tide shows up repeatedly in this poem. The slow, steady, endless movement of water, in and out, in and out, becomes a symbol of eternity. It also, though, comes to represent change and loss. Let's turn to the play-by-play.
- Line 2: Here the tide is just the tide. It's part of the landscape at the beginning of this poem. At the same time, the fact that our speaker describes it as "full" contributes to the feeling of calm and happiness in these first few lines.
- Line 17: Here the "ebb and flow" of the tide is used as a metaphor for the way that unhappiness rises and falls in human life. We think the rising and falling of the tide makes for a kind of guiding rhythm all through this poem.
- Line 25: Here's another metaphorical tide, representing human faith. In this case, though, it doesn't go in and out. It just rolls back forever, deserting the world and leaving us confused and alone. Yay?