Jesus draws a sharp contrast. The Gentiles, the unbelievers, seek after all these things, and their anxiety is perfectly rational. If you have no Father who knows, then survival really is on your shoulders, and you had better manage it yourself. The pagans babbled their prayers and tried to win the attention of indifferent gods. Their worry ran on a simple assumption: no one is in charge of my future, so I must be.
But the disciple’s situation is categorically different. Your heavenly Father knows. Not might know, not will eventually know, but knows now what you need. The provision is already in view. From the Father’s side, the only open question is whether you will trust Him. When a Christian lives in the grip of anxiety, Jesus is showing us how illogical that is, because we are reasoning like people who have no Father at all.
Many of us protest at this point. We have prayed, we have trusted, and things still got worse. The diagnosis did not change, the money ran out, the job was lost. Jesus is honest with us here. He is not promising a trouble free life. He is promising a Father who is adequate, whose grace is sufficient. That is a different promise, and at the end of the day it is a better one.