"You are my best friend. I promise to go fishing. I promise to tell funny jokes. I promise to care for you. Thank you for being in my life," Hannah giggled as she said her vows.

But these were no ordinary vows.

Hannah's story

Hannah and Ashley are sisters from Indiana with a tight bond, but their bond is much deeper than the average sisterly relationship.

"Hannah and I are best friends first, sisters second," Ashley said. "We do everything together and I could not have asked God for a better sister. Hannah brings out the best side of me."

"Hannah has Down Syndrome and diabetes and will always need to be under my parents or my care. Someday when my parents are no longer here, I will be Hannah's full time guardian," said Ashley in a post featured on Love What Matters.

And she has been under Ashley's watchful care for a long time now. Ashley and her husband, Will, met seven years ago, and Ashley made sure that Hannah always felt included.

"When I first met Will, I introduced him to my sister Hannah and I told him we were a package deal," she said.

Will's story

A lot of men wouldn't be too keen on sharing so much time with an in-law. So how did the newlywed husband feel about his wife's sister being such a big part of their relationship?

"Will had no problem and took Hannah in as a sister, including her on dates, always remembering flowers for her on valentines day [sic] and everything in between. He protected her and cared for her like the best big brother," said Ashley.

After being with Ashley for seven years, Will knew how important it would be for Hannah to be an integral part of the wedding.

Back to the wedding

Just as she was a part of Will and Ashley's relationship when they were dating, Hannah was a big part of their wedding.

"She walked down the aisle with Will's grandfather and stood behind me during the ceremony. She then exchanged vows with Will and told him she always promises to go fishing, tell funny jokes, and always care for him. She thanked him for being in his life," Ashley explained.

"Will did the same, promising the same promises and telling her she's one in a million. They vowed to be best friends forever and hugged."

And all three lived happily ever after

Ashley says she is grateful that she and Will have such a good friendship and that "Hannah is just the perfect addition."

They hope their message of friendship and love continues spreading.