Jesus is commanding us not to worry or be anxious about our material needs being met. It would be impossible to have no thought whatsoever about our physical needs. Even Jesus thought about His need for money to pay taxes (Mt. 17:24-27). We are simply not to be preoccupied with thinking about riches or spending our time worrying about necessities. These things will be added unto us as we seek first the Kingdom of God.
The way we take or receive an anxious thought is by speaking it. Doubtful thoughts will come, but we do not sin until we entertain them. According to this verse, speaking forth these thoughts is one way of entertaining them; therefore, don't speak forth these negative thoughts.
It is important that we watch the words we say. Begin to speak words in faith that line up with God's Word, then positive results will follow. If we speak words of doubt, we will eventually believe them and have the negative things that these words produce. There are no such things as "idle" words which will not work for or against us. Death or life is in the power of every word we speak (Prov. 18:21). Our words can be our most powerful weapon against the devil, or they can become a snare of the devil (Prov. 6:2).
