Many Christian parents have little trouble quoting verses which teach about how they are to raise their children or how their children are to respect them as parents, but what happens when the child you've raised hits 18 and becomes an adult? There aren't quite as many familiar Bible passages about parents and their adult children. Still, the Bible is not silent on how parents and adult children relate to one another.
Proverbs 22:6 says, "Start children off on the way they should go, and even when they are old they will not turn from it." When your children are young, you have a lot of control over their lives and choices. As your children get older, that control diminishes. As your child approaches that age when she is almost ready to move out and face the world as a young adult, you may find yourself out of the loop when it comes to giving direct guidance. However, Scripture promises that if you've trained them in the way they should go when they are young, you can have confidence that they will continue to follow the right path when they are older. That doesn't mean they'll never veer from the paths you'd like them to take, but it does mean that what you taught them as children will remain with them.
One of the toughest Bible verses for parents of adult children to put into practice is Genesis 2:24 (repeated in the New Testament in Ephesians 5:31): "That is why a man leaves his father and mother and is united to his wife, and they become one flesh." When children grow up and get married (as most of them will), the Bible teaches that they are to leave their parents and unite themselves to their mate. All too often, parents cause problems in their children's marriages by refusing to let go or taking sides in disputes between their adult children and their spouses. Even if marriage isn't on your young adult son or daughter's radar yet, it's important to prepare yourself emotionally now to let them go when the time comes.
Most people are familiar with Deuteronomy 5:16: "Honor your father and your mother, as the Lord your God has commanded you, so that you may live long and that it may go well with you in the land the Lord your God is giving you." St. Paul called it the "first commandment with a promise" in Ephesians 6:2-3. While most think of younger children when they read this, it doesn't have an expiration date. Parents never stop being parents and their children -- even as young adults -- never stop being their children. While adult children should be expected to go their own ways as they turn 18 and get ready to leave the nest, they should continue to honor their parents. As it says in Proverbs 23:22, "Listen to your father, who gave you life, and do not despise your mother when she is old."
In Matthew 5:5-8, Jesus addresses a group of religious people who tried to work their way around the practical implications of God's command to "honor your father and mother" by offering money they could have used to help their parents as a "gift to God." Jesus' main point was that it's wrong for people to try to manipulate their way around God's commands, but the example he used also makes clear that adult children should help their parents when they are able to.