One marriage wish is the Irish Blessing, "May the saddest day of your future be no worse than the happiest day of your past." Another marriage wish quote states "May the love you express to each other today, always be the first thoughts during any hard time in the future."
Quotes as marriage wishes are useful to have when attending a wedding and giving a speech, and also for writing a congratulatory note in a wedding card. A good quote to write in a wedding card states, "Heartfelt congratulations on your marriage. May your bond last forever, and should it ever change, may it change to a firmer and better one."