Stone Ceremony

A recent wedding that I officiated (today) brought me something new to experiment with. I always love when the bride and groom share a new tradition, or something special that I can offer to future clients as a way to create a unique ceremony.
This time it was a stone ceremony. I didn't know what it was, what it would look like, and I had anxiety about making it perfect for the couple.
It turned out perfect anyway (You can say "I told you so").

6 people were chosen initially to write a blessing or a prayer/word representing what they wished for the couple on a stone to carry with them throughout their marriage. The maid of honor, Best man (who also happened to be the couple's brother and sister), and each parent of the couple. They each stepped forward, presented their word and stone to the couple, and through emotion, explained why they chose that word.
It was beautiful. We also invited each family present to write a word/blessing on a stone after the ceremony.
What a great way to create a visual foundation of the marriage. I explained that the stones are solid, that the blessings and support from their community strengthened it, but that stones together can easily shift and slide, so that it was up to the couple to create a balance when standing on the foundation.

It turned out lovely.

What would be your word/blessing on a stone for a marriage, and why?