That would be Exodus 20:12: Honour thy father and thy mother: that thy days may be long upon the land which the LORD thy God giveth thee.
At different ages of your life, that will mean different things.
When you’re a little squirt, that’s obedience without a lot of whining, carrying on, or being a brat. It’s true. You won’t always get the coolest new must-have toy or your favorite candy in the check-out aisle. You’ll live. (Ephesians 6:1, Colossians 3:20)
For teenagers, that’s making sure that while you’re finding your identity, you don’t do stupid things that would hurt your witness to the world or embarrass yourself and your parents. That also means obedience to the house rules. If curfew is 10p, then you’d better get there at 10p or be on the phone to explain what huge crisis kept you away. (Luke 2:51 – Jesus was “of age” in the Jewish society at 12-ish years old. He was considered a “Son of the Law” and could officially count as one of the 10 men needed to form a synagogue. No, not a son-in-law, that’s different.)
Most of us are well past that and into the stage where we are adult-type people, physically if not mentally. Respecting our parents now means picking up the phone to visit or dropping by … not just when you don’t have a better offer from somewhere else or need free babysitting, but just to see them. As our parents age and start needing us to watch over them, that means taking care of them. If that results in skilled nursing facilities or nursing homes, then that means staying on top the place to make sure your parents are getting the care they need and visiting frequently so your folks don’t feel like they were dropped off in a walking mausoleum.
Consider Mark 7:10-13. Jesus gives the Pharisees What-For for letting their manmade traditions overrule God’s law. One example he chooses is the rule of Corban. According to Jewish law, a man was commanded to take care of his aging parents. However, according to Jewish tradition, money or goods could be declared “Corban” meaning that they were set aside as a special gift to the Temple. The guy could use the stuff in the meantime, but eventually, the stuff or money was going to the Temple. So, what would happen? A person would buy really fancy stuff for himself and enjoy it greatly. If his parents needed help or care, then he would explain that the money or goods were Corban, so the parents were on their own while he enjoyed the extra-spiffy stuff, which at least in theory was to go to the Temple at some point. Parents, however, went without. That’s not honoring mother and father, but indulging in greed.
This must be pretty important to God. It’s the only commandment with a blessing for those who adhere to it. (Some of the others have promises to those who don’t keep it.) The way we treat our parents reflects on how we feel about God, who is our Almighty Father. Because of Jesus’ sacrifice, we have the capacity to become “Bene ha Elohim” or “Sons of God” in the directly-created-by-God sense. That term, by the way, is used in the OT only of Adam and the angels. In the natural, the rest of us mere mortals are not Sons of God but rather sons of Adam. Jesus fixed that so he could be the first among many brothers. (John 1:12, Romans 8:29)