Oswald Chambers has an excellent explanation of Matthew 6:33 :
“Seek first the kingdom of God and His righteousness, and all these things shall be added to you.”
It and his other 364 entries can be found at http://utmost.org/having-god%E2%80%99s-unreasonable-faith/. Editing and emphasis will be mine throughout….here goes:
“When we look at these words of Jesus, we immediately find them to be the most revolutionary that human ears have ever heard. “…seek first the kingdom of God….” Even the most spiritually-minded of us argue the exact opposite, saying, “But I must live; I must make a certain amount of money; I must be clothed; I must be fed.” THE GREAT CONCERN OF OUR LIVES IS NOT THE KINGDOM OF GOD BUT HOW WE ARE GOING TO TAKE CARE OF OURSELVES TO LIVE.
Jesus reversed the order by telling us to get the right relationship with God first, maintaining it as the PRIMARY concern of our lives, and never to place our concern on taking care of the other things of life.
“…do not worry about your life…” (Matthew 6:25). Our Lord pointed out that from His standpoint it is absolutely undreasonable for us to be anxious, worrying about how we will live. Jesus did not say that the person who takes no thought for anything in his life is blessed— no, that person is a fool. But Jesus did teach that His disciple must make his relationship with God the DOMINATING focus of his life, and to be cautiously carefree about everything else in comparison to that.
In essence, Jesus was saying, “Don’t make food and drink the CONTROLLING factor of your life, but be focused absolutely on God.
Jesus is saying that THE GREATEST CONCERN OF LIFE IS TO PLACE OUR RELATIONSHIP WITH GOD FIRST, AND EVERYTHING ELSE SECOND.”
All the best, in Him.