The Jew of Malta is predominantly written in blank verse (unrhymed iambic pentameter). The use of blank verse lends the play a distinct rhythm, one shared with plays penned by Marlowe's contemporaries (most prominently, Shakespeare). By choosing to write the majority of the play in blank verse, Marlowe provides himself the opportunity to emphasize particular characters or passages through rhyming or changes in metrical structure.
In Act 4, Scene 4, when Ithamore proclaims his love for Bellamira, he does so using a series of rhyming couplets. This has the effect of simultaneously breaking the stylistic baseline and evoking the sonnet, a form often used in romantic poetry:
Content: but we will leave this paltry land,
And sail from hence to Greece, to lovely Greece.
I'll be thy Jason, thou my Golden Fleece;
Where painted carpets o'er the meads are hurled,
And Bacchus' vineyards overspread the world;
Where woods and forests go in goodly green,
I'll be Adonis, thou shalt be Love's Queen.
This stylistic shift from blank verse to rhymed couplets accompanies a shift in tone from more dramatic or tragic to something a bit more romantic. Readers who are familiar with romantic poetry will likely be accustomed to hearing sentiments of love and ardor expressed in rhyming couplets, and Marlowe's stylistic transition appeals to that romantic tradition.
