The expense of spirit is a sonnet by William Shakespeare. It consists of 14 lines organize into three quatrains and a final rhyming couplet, so the sonnet follows the Elizabethan model.  The first line is similar to the title so, the reader understands it is part of a collection.

Considering the denotative level, the function of the first quatrain is to describe lust, when it is an effect of waste and it seems to advance an argumentation. It is made up of a list giving possible qualities of lust: “perjured, murd’rous”,… The quatrain starts with a statement “the expense of spirit…is lust in action” and from this statement the  develops of an argumentation follows focusing the reader's attention on the act of a sexual intercourse. The poet uses strong language to qualify lust, not only to describe it, but because lust is difficult to control. Indeed it is a strong  sexual desire. The strength of lust is made up with harsh sounds (like B or R).

In the quatrain there is the repetition of the word “action” because the poet wants to underline the physical implication. The repetition gives also energy to the line.

Finally the rhyme scheme is an alternate rhyme.

In the first quatrain the speaking voice explains his thoughts:  when sex prevented the birth of somebody, it is sinful.

In the second quatrain there is a contradiction indeed people are continually looking for lust but, when it is over, it is hated. In this quatrain there is the expression “enjoyed lust” that means the orgasm. The poet doesn’t use this word because it is the scientific term, not suitable for literature. Besides, the poet uses the verb “hunted” that is usually used to speak about a house leaved by ghosts. As a hunted house is lived by ghosts, men’s body is lived by spirits who flower the desire of lust. The verb can be connected with the title, when the speaking voice speaks about a spirit. The metaphorical structure is used to explain that lust is a out of control desire. Rationality is powerless and human beings are subjected to such instinct so that the result is underlined in the last word “mad”.

The third quatrain reinforces the description of lust. The speaking voice says that people become made to look for it and make extreme things to have it. In the quatrain, again there is the contrast between the deep joy felt during the sexual intercourse and the sorrow of its end. It is interesting to notice the repetition of the verb “have” conjugated in different tenses. The repetition may underline people’s desire to look for lust. An extreme one.

The sonnet ends with a rhyming couplet where the speaking voice gives a conclusion. Indeed even everyone knows lust, anyone knows how to avoid it, underlined by the chiasmus “all well knows…none knows well”.

 Also in the couplet there is a contrast: indeed there is the word “heaven” followed by the word “hell”.  The contrast explains that lust may be heaven (during a sexual intercourse) but it leads men to hell

In conclusion, the whole sonnet exploits an antithetical structure that underlines that lust has a big power on men.