Do you think it's important for children to have their parents' blessing on their marriage?
Yes. Important, but not absolute.
I've always counseled young people to work hard at that. Don't treat it lightly. If Dad or Mom on her side or his side is saying, "I don't think this is the right man or woman for you," don't blow that off. Give it time. Pray for a miracle of change. Involve other people.
In other words, I'm not absolutizing it and saying that, as an adult under God's leading, that Mom's and Dad's work now—now that you're an adult and you have your own relationship and you're about to form a new unit where you leave mother and father—that that overarching thing is absolute. I'm just saying, it really is sweet. It's really important.
Honor your father and your mother by taking very seriously what they say. Give it a lot of time. And I don't know how much time to give it. Give it a lot of prayer. And I don't know how much prayer to give it. Involve other people in the efforts to try to bring some understanding here.
Listen to the mom or the dad and try to discern, "Is God speaking here about timing or about the person?" And if you discern after significant time, significant prayer, and significant others involved, that she or he is of God for you and Mom and Dad are missing it—they're misreading, they don't know what this person is really like, or they're operating out of a worldview that is not biblical—then keep honoring them through that. But, I don't think it means you absolutize their authority in that adult relationship.