Metaphysical poets wrote about love , religion and the Universe in a way that could be very complex and violent. They used the language of science , astronomy , theology and philosophy. By the use of metaphors , comparisons ans similes, metaphysical poets wanted to create strong images into the reader’s mind.The most important aspects were the use of wit (skill with words, the ability to create unusual and unexpected images) , the use of metaphors, comparisons and similes,  irony ,colloquialism.

The term metaphysical was used by John Dryden. In his essay Dryden considered metaphysical poetry too difficult and complicated. The men who had a positive view of metaphysical poetry was Samuel Johnson, better known as Dr. Johnson.

John Donne was the most important poet among the metaphysical poets. He was highly innovative when spoke about love , God and religion. He wrote love sonnets combining sensual and spiritual images appealing to senses.

A VALEDICTION FORBIDDING MOURNING. 
by John Donne

AS virtuous men pass mildly away,  
    And whisper to their souls to go,  
Whilst some of their sad friends do say, 
    "Now his breath goes," and some say, "No."                     

So let us melt, and make no noise,                                       5 
    No tear-floods, nor sigh-tempests move ; 
'Twere profanation of our joys  
    To tell the laity our love. 

Moving of th' earth brings harms and fears ; 
    Men reckon what it did, and meant ;                              10 
But trepidation of the spheres,  
    Though greater far, is innocent. 

Dull sublunary lovers' love  
    —Whose soul is sense—cannot admit  
Of absence, 'cause it doth remove                                     15 
    The thing which elemented it. 

In John donne’s work “ a valediction forbidding mourning “ the poet wants to highlight the power of his love . He invited his woman not to cry ; distance won’t be a problem for them , they are united and their love is strong because it is not only a kind of physical love but it is also spiritual love. Distance, problems and difficulties will make them stronger . On the other hand physical love is fragile and weak.

The poet starts his work with a simile between virtuous men at the point of death and their separation: as virtuous men's death doesn't provoke pain to their friends, the narrator and his woman should not suffer and cry for their separation because their love is not only physical. He wants to invite his mistress not to cry and not to make noise because their love is personal. As a consequence the poet uses a lot of repetitions in order to make the reader understand that their love is private. -à The repetition of sound  s conveys a sense of silence and creates a soft and calm atmosphere. In the second stanza the poet  uses images from the nature in particular from the semantic field of water. In  this case nature is negative. ( floods, tempests)
At lines 7-8 the poet uses words from the semantic field of religion ( profanation, laity) in order to make the reader understand that their love is pure.
Then the speaking voice carries on using another metaphor in order to convince his mistress not to feel pain because fear  is caused by hearthly and mortal things like an heartquake. The intelligent reader can notice from this lines the characteristics of metaphysical poets that make a lot of references to nature.
 in the fourth stanza the poet says that generally people consider senses more important than soul. But in this case theur love is not only a physical love but also a kind of

Spiritual love. That’s why their love will resist even if they are distant.