Behold the symbol of wedlock. The perfect circle of love, the unbroken union of these souls united here today. May you both remain faithful to this symbol of true love. . . .
I take as my wedded partner to have and to hold from this day forward, for better or for worse, for richer or for poorer, in sickness and in health, to love and to cherish, till death do us part.
For as much as [we] have consented together in wedlock and have witnessed the same before this company of friends and family and have given and pledged their promises to each other and have declared the same by giving and receiving a ring and by joining hands....
The exchange of rings during a traditional wedding ceremony often includes the vows above. They are, of course, powerful because of the commitment two people make as they enter into great unknowns: their future in love.
These words are made more powerful by the use of alliteration, noted in the passage by underlined words. The repetition of an initial sound facilitates both rhythm and emphasis.
Power also derives from parallel construction. In the second paragraph, infinitive phrases and a series of prepositional phrases using antonyms focuses the message and the mind upon the solemnity of the vow being spoken. In the third paragraph, a series of verb phrases, each beginning with have, achieves the same effects.
Transform your own writing by rewriting a passage to use alliteration and parallel construction.