In Judith Viorst's poem, "A Wedding Sonnet For the Next Generation," the poet's movement pivots or shifts starting on line seven. The first six lines were allusions to famous sonnets written by Shakespeare, Yeats and Elizabeth Barrett Browning. The words are not really those of Viorst, but she uses them to draw the reader's attention to the love poetry of poets of the past. I assume she does this to point out that things are not the way they once were: today the modern couple is looking for something other than flowery poetry—they may be looking for something more "authentic" and personal.
The image with the most clarity, "And you are writing your own poem," makes me think that the bride (and perhaps also the groom) is writing her vows. In the past perhaps the bride-and-groom-to-be leaned more toward using the words of poets of the past, or even contemporary, popular poets. Viorst notes that "there are poems so fine, so true" out there, and they will help the bride (or the groom) to express her feelings of love and to present her promises or her "vows."
However, the author points out that in writing one's own poem, rather than relying on the words of others, that the feelings are more genuine because they are unique. The words belong not to men and women long dead who spoke of those they loved; the words may not have a "studied" and perfect rhyming pattern or the "correct" number of beats ("scan") perhaps. Viorst is suggesting that this is not what matters. When a couple writes their own vows, they are inspired by their unique love for each other. And while some of the words they choose may be "sublime" like those used in the past by others, the content will have more meaning for this couple. Rather than lofty promises and praise of older poems, the words here will echo with a new sincerity: honing in on things that matter more today, for this "next generation"...
Respect. Trust. Comfort. Home.