Willam Blake has written This poem as a regard to 2 forms of love, one selfless and another selfish. The first stanza says that the clod is selfless as it allows hi self to be trampled by cattles feet. This contracts with the pebbles point of view when it says that love is only for our own selfish purposes. Just as it says "Build a hell in Heaven's despire"
well ,this is a general idea of the poem the clod and the pebble.