Again, this “makes” refers to the woman’s firmness. If she is firm then he will be able to end where he began. In other words, if she is faithful, he will return to her. While these two concluding lines are famous for their romantic sentiment, the conditional nature that the “makes” brings into this line implies a deeper meaning than just romantic sentiment.

“Firmness” here refers to steadfastness or faithfulness. “Just,” meaning both righteousness and accuracy, becomes dependent on this firmness. In other words, the speaker suggests to his mistress that if she is able to remain firm, faithful, and steadfast, then his circle, his journey back to her, will be righteous and accurate.

In this metaphor, the speaker compares his lover to the fixed foot of the compass and himself to the free foot of the compass, suggesting that though he is away physically, he is still tethered to her. Like the compass, she will be his guide leaning after him and keeping him on track as he roams.

If you were drawing a circle with a mathematical compass, you would “fix” one foot to one point on a piece of paper and then rotate the other foot around it in order to draw the circle. The “free” foot that is moving, always circles around the fixed foot because they are attached.

Donne uses this simile to compare the lovers’ souls to the two legs of a compass. He is not talking about a traditional navigation tool here but rather a mathematical compass used to draw circles. The two feet of this compass are attached at the top, meaning even if they are apart, they are still connected and work as one unit.

In the Petrarchan sonnet tradition, the speaker would often break his love object into her distinct parts in order to describe each one as perfect and beautiful. He would focus on her physical parts and compare them to greater concepts, such as her lips red as a rose. Here Donne uses a catalogue of human parts as an anti-blazon that pushes back against the Petrarchan tradition in order to declare that their love does not care about these physical markers (or this poetic representation of perfect love).

This is a compound word that Donne seems to have made up as it historically only appears in this poem. “Inter” means between; “assured” means to secure, promise, or make safe. Thus, this word suggests that there is a promise or security between the speaker and his mistress that is made up of their minds rather than their bodies. This once again situates their love outside the human realm of the body.

“Elemented” in this context means created or produced. “Those things,” which seem to create the love, are vague here. However, since the speaker has characterized the lovers as of the earth, “those things” can be inferred as referencing the body or carnal acts. In other words, their love is entirely made up of their bodies.

The “sublunary lovers” cannot “admit” (permit or accept) “absence” (distance from one another) because their love depends on their ability to touch. The speaker uses this description to qualify his characterization of the lovers’ love as dull, since their love cannot survive if their bodies are not close to each other. By outlining this impure love, the speaker implicitly makes his own love seem more pure.

“Sublunary” means that which lies between the earth and the moon’s orbit, as in on the surface of the earth. The speaker uses this cosmic picture to both transition from his conceit about the spheres and refer to ordinary lovers who are subject to change because their love is directly related to the inconstant moon.

A dominant theory of astronomy from the 9th to 16th century stated that there were 9 hollow globes that moved around the Earth in elliptical circles. Trepidation was the oscillation, that is a change or variation in a sphere’s predictable movement. The speaker compares the movements of the earth, as in earthquakes, tidal waves, etc, to the movement of the “spheres” to show that while the movement of the spheres is colossally larger in scale, it causes less harm than movement on the Earth.

This is the first instance in which the speaker distinguishes their love as that which makes them better than mere mortals, a theme which will continue for the rest of the poem.

By this the speaker means someone who is not of the clergy, or religious orders. The speaker uses this word to distinguish his love from the lay or mortal world and implicitly make the lovers part of a religious or other worldly realm.

This is a contraction of “it were.” Donne’s need to shorten these two already short words comes from the meter, or rhythm, of the line which is written in iambic tetrameter, meaning there are four stressed syllables per line. “‘Twere” fits better because the stresses in this poem fall on the second syllable of the line. Since the “pro” of profanation must be stressed, “it were” would not work metrically because then both “were” and “pro” would be stressed throwing off the meter of the line.

By melt Donne means to disintegrate or liquefy. This metaphor is another reference to Carpe Diem poetry as the speaker here suggests that the two lovers become one. However, “melt” at this time also meant to disperse into particles, to vanish or disappear. Thus, the line proposes that the lovers simultaneously become one and move away from each other. This dual meaning foreshadows the conclusion Donne will draw at the end of the poem.

The speaker turns abruptly away from this scene to speak to his lover about their love. This movement of focus from death to life is reminiscent of Carpe Diem poetry in which the speaker reminds his love object and addressee of the immanence of death in an attempt to get her to appreciate the beauty and importance of their love.

Donne begins by describing a group of people crowded around a virtuous man on his deathbed debating whether or not the breath they witness is his last. This situates the reader in an earthly world in which all participants are extremely concerned with the body.

In an example of unexpected imagery used by the metaphysical poets, Donne concludes his poem with the speaker assuring his lover that her love controls his circle (his travels), and, like a compass circumscribing a circle, his travels naturally bring him to his point of origin—her.

Donne continues the metaphor which likens his and his wife's love to a compass.  As one leg of the compass moves to make an arc, for example, the other leg leans toward it to accommodate its motion.

Here, the speaker refers to compasses used to draw lines, arcs and circles, like the compass one might use in a geometry class.

Through simile, the speaker compares his love to the strength of gold, which when beaten, expands rather than breaks. By using this simile the speaker asserts that because their love is of the mind and soul, not the body, when he and his wife move physically apart, their love will not break but rather expand like beaten gold.

These two lines explain how their love lives within their minds, such that they won't miss each other when they can't see one another or touch each other's eyes, lips, or hands.