Apostrophe is the guiding light of "Holy Sonnet 14." The speaker boldly speaks to God using a commanding and desperate tone, one that is laced with sexual connotations.
The use of apostrophe to address God in a poem is nothing new. Devotional poems—poems that function as prayers—often use apostrophe, just people directly address God when they pray. George Herbert, an English poet who lived at the same time as Donne, wrote devotional poems in which humble speakers praise God and interrogate their own faithfulness. Tonally, however, Donne's poem is distinct. Herbert would never have addressed God as Donne's speaker does, in the manner of sexual partner.
This poem doesn't address God like the almighty, purely good creator of the universe. Instead, the speaker treats God like a potential lover who's not being bold enough in his flirtation with the speaker. If God is going to win over the speaker (i.e., if the speaker is to feel faithful again), then God can't just "knock, breathe, shine, and seek to mend." No, he needs to seduce the speaker with a dashing rescue followed by rough, "ravish[ing]" sex. Of course, all this is metaphorical. Or, at least, the speaker isn't speaking on physical terms. If the poem is erotic, it's erotic on a spiritual level.
The way the speaker addresses God here gives a flavor of the kind of the spiritual relationship the speaker needs. Donne spent his early poetic career writing pretty explicit poems about seduction and sex. In those days, the addressees of his apostrophes were female lovers. Considering this personal history, then, it makes sense that even as Donne's speakers turn towards more religious considerations, the same underlying erotic urge is still there. Now, however, that urge is directed to God rather than women, and it becomes spiritual rather than physical.
Additionally, it's interesting to note that the implied gender roles have been flipped. Whereas Donne's earlier erotic poetry has generally been interpreted as addressed by a male speaker to a woman, in this poem Donne's speaker takes on characteristics associated with Medieval and Renaissance femininity (helplessness, weakness of reason, the need to be rescued, sexual passivity) and God, the adressee, takes on a male role (strong, powerful, coming to the aid of women). In this sense, then, the poem reaffirms cultural assumptions about gender while also playing with them.