A Valediction Forbidding Mourning is a song written by the metaphysical poet, John Donne.

In the first quatrain the poet describes how virtuous men die; but it is only a simile.

In fact in the second quatrain the reader understands the situation: the simile is used to compare the death of virtuous men to the separation of the two lovers, and that lovers' separation should be quiet.

In the fourth quatrain, Donne expresses the idea of love; he says that love is based on the five sense.

Therefore, when lover separate, they remove from each other the very basis of love.

In the next stanza the speaker reassures his love: in fact he thinks that their love is a pure love and so it isn't based only on the sexual attraction.

In the sixth quatrain the speaking voice adds that their two souls have combined to form one soul, so, even if he must go, their love will not shap, but expand.

In this song, Donne writes an ingenious simile to describe the situation: he compares the lovers' two souls to the the feet of a drafting compass; like it, their souls are joined at the top, so their love is a spiritual union.

He develops the compass conceit in the next quatrain, and he concludes it in the last stanza:

His love's fidelity will allow him to carry out his journey and return home happily.