A figure of speech is a phrase which describes something in a figurative, or non-literal, way. Metaphors and similes are the most common types of figures of speech.

In "How Do I Love Thee?" by Elizabeth Barrett Browning, the speaker uses similes to compare her love to different situations or concepts. For example, she compares her love to her "childhood's faith" and to "the depth and breadth and height" to which her soul can reach. The comparison between her love and her "childhood's faith" implies that her love is innocent, pure, and unquestioning. The soul is a metaphysical concept, so its reach is, in theory, infinite. Thus, when the speaker compares her love to the reach of her soul, the implication is that her love is, likewise, infinite.

The speaker also uses a metaphor when she says that she loves the addressee with "a love [she] seemed to lose / With [her] lost saints." The speaker has, of course, not lost any literal saints, but she has lost what the saints symbolize: namely, the purity and innocence that she perhaps once had faith in, before she became older and more cynical. The implication of the metaphor is that her love for the addressee has restored her faith in these virtues.