The Pearl
In this poem, a father is mourning the loss of his child, who he calls a "pearl." Ultimately, the image of a pearl is used to symbolize how precious and valuable the child was to the father.
God and Christianity
For the father, God and Christianity ultimately represent a sense of comfort, hope, and condolence. As he has lost his child, he looks to God to give him consolation for his loss.
Dreams
Dreaming is a key motif of this poem, and is also a motif across many Middle-English poems. In this poem, dreaming represents a state where the father can learn about Christianity and find a sense of comfort and hope.
Grief
The emotional state of grief is a key motif in this poem. Ultimately, the father is trapped in a state of grief after the loss of his child, but he finds comfort in his dreams of God and heaven, which gives in an escape from his all-consuming grief.
Heaven
For the father, heaven represents the final and ultimate state of happiness and comfort. He finds consolation in the fact that his daughter has been allowed into heaven, and had found happiness there.