Here's a lovely mediatation on this Gospel by St. John Chrysostom:
If spiritual things hold first place in our lives, material needs will cause us no concern, for God in his goodness will give them to us in abundance. On the other hand, if we devote ourselves entirely to earthly pursuits and neglect our spiritual life, if we are always concerned with what this life has to offer without any care for our souls, then we shall forfeit not only spiritual graces but worldly profit as well.
God wishes us, then, to be free from every anxiety regarding temporal affairs, and to have all possible leisure for the things of the Spirit. He says: “Your part is to seek spiritual blessings, and I myself will provide amply for your material needs. Look at the birds in the sky. They neither sow nor reap nor gather crops into barns, and yet your Father feeds them.” In other words, “If I take such care of irrational birds as to supply them with all they need without ploughing or sowing, I will take much greater care of you who are endowed with reason, if only you make up your minds to put spiritual things before temporal ones. If I made these creatures for your sake, as well as the whole of creation, and if I take such care of them, of what great care will I not deem you worthy – you for whom I created all of this?”