Peter is preaching on Matthew 6:25-34, which promises us troubles in this world, but admonishes us not to worry.
Peter pointed out that there are things about which we should be concerned, but the worry Jesus tells us to leave behind is preoccupation with food, fashion, fitness and future. Society is quite preoccupied with all of this. Lifestyle aspirations consume us. Jesus said those that don't believe in God run after all these things. Jesus isn't saying we should be disinterested in the welfare of our families, He's saying God will cover all of these needs without us worrying about them. They should never become gods to us. If we buy into the values of the world we're trying to worry the gods into doing our bidding. As our District Superintendent, Art Alexander said, "Worry is prayer to the wrong god."
Worry never strengthens us for tomorrow, it only weakens us for today.
We can't do anything for tomorrow, but we can do something about today. Worry is wasteful of our time, because it has us moving in the wrong direction