And do not seek what you should eat or what you should drink, nor have an anxious mind. For all these things the nations of the world seek after, and your Father knows that you need these things. But seek the kingdom of God, and all these things shall be added to you.
Luke 12:29-31 (NKJV)
Jesus is telling us to not be concerned with what we might consider the lower needs of day to day life, and to instead dedicate all our attention to our higher needs. Our higher needs are spiritual, whereas our lower needs, though certainly real and legitimate, are physical. This does not mean that we are to be lacking in any area, but much rather that our Father simply does not want us to be concerned with things He knows we require. God desires for His children to trust Him, and to find a calm and confident reassurance in this trust. The more we can learn to trust God with our day to day needs, seeking Him and delighting in Him above all else, the more we will find that whatever we have need for will be added unto us.