I believe that God wants us to be positive in our speech. When you meet a person on the street and say that they look terrible, what happens? They are not pleased and may feel depressed. If you can say something positive to them they feel much better. I believe it is the same way in which we approach out Lord. If we are negative in our prayers we do not usually get an answer. We need to pray the Word of God which is positive. Paul refers to the Word of faith. What is it? He said it was the word that he preached. It should be in our hearts and in our mouths.