In "Verses Put into a Lady's Prayerbook," John Wilmot advises a lady that the prayer book will be a "useless book" until and unless she begins to display mercy:
Heaven is just, and can bestow
Mercy on none but those that mercy show.
In the meantime, the poet warns the lady, "In vain you vex the gods with your petition"; in other words, your prayer is only bothering God until you begin to show mercy to other people.
Although it is not explicit in the poem, it seems that the person who has not been treated with mercy by the lady is none other than the poet himself, who is in love with her. The poet mentions that the lady is "fair" (beautiful) and has "bright and charming eyes"; he concludes the poem with the hope that he and the lady may someday experience "all the joys on Earth."
Each line of the poem contains between 7 and 11 syllables. There are three distinct rhyme schemes within the poem:
Lines 1-6: aa, bb, cc
Lines 7-9: ddd
Lines 10-13: ee, ff
Lines 14-17: g-h-g-h
The poem makes good use of alliteration; for example: presume-pray, vain-vex, save-soul.
I would not consider the poem particularly rich in imagery, although the opening image of flinging away a prayer book is a strong one, and must have been considered somewhat daring in 1697 when the poem was written.