The first thing I would talk about is the almost repetition of the first and third stanzas. You could argue that Blake shows these two perceptions of love to demonstrate the fine line between love, being controlling and being used by another person.
I like this interpretation. If the clay says love ‘seeketh not to please itself’ and the pebble argues that love ‘seeketh only to please itself’, then they are directly opposed. Does Blake want us to choose? I think not, I think he is really trying to say that we need to avoid viewing love in these terms. Love should be selfish in the respect that we should look to our personal happiness, but at the same time we cannot be selfish and not respect the freedom of those we love.
To further this interpretation, consider the two singers. Notice that Blake chooses to capitalise ‘Clod of Clay’ and ‘Pebble’, which is a method of personifying them. They are already personified by the fact they are singing. He does this because we then consider them as if they were humans.
If we consider the qualities of clay and relate them to humans, we should think about it being soft, malleable (easy to mould and change) and being considered largely insignificant. Not only this, but Blake tells us this clay is ‘trodden with the cattle’s feet’ suggesting that this person, or people with this attitude to love, are walked all over and taken advantage of. The word ‘trodden’ in particular, invokes ideas of being taken for granted and being abused. Also, Blake chooses to add the adjective ‘little’ to describe the clay, further diminishing its importance in the world.
In contrast, we have the pebble. Now pebbles are definitely more attractive given how smooth they are, but they are also cold and hard. This pebble is ‘of the brook’ and therefore, as an multisensory image, we can feel both its smooth contours coursed by the flow of water, but also its coldness. Human connotations here would be hard, cold and emotionless. This sounds like someone who has been hurt by love and is cynical about the emotion. Notice how this interpretation of love considers it to ‘bind’ which makes me think that this singer feels trapped by the love of another and to have lost their freedom.
The final thing that you might wish to comment on is the hyperbolic (over the top) conceptions of love. Both songs finish with the idea of love creating either a ‘Heaven in Hell’s despair’ (thus banishing all aspects of unhappiness for another and of greed within oneself) and the other creating a ‘Hell in Heaven’s despite’. To consider love as one of two extremes, causing eternal bliss or eternal misery, is hyperbolic and unrealistic. We can easily appreciate these twin aspects of love, in its ability to make us happy and miserable at certain times, but the truth is really between the two.
I hope I’ve been clear here on how important what has not been said, is to the poem. The views represented are the two poles of love, but Blake is trying to warn us not to stray to either extreme, but to find some middle ground.