Luke 1:20

Listen carefully, you will be continually silent and unable to speak until the day when these things take place, because you did not believe what I told you; but my words will be fulfilled in the proper time.

If our thoughts are not lining up with the word and promises of God, we will speak against them. God cannot change our circumstances if we are speaking negatively and not believing in faith. When the mind agrees with God, the word of God will come out of our mouths. We will have confidence that what God has promised He will do for us.