What we say matters. The word of God is what formed the earth! And it’s that same breath that’s in us now. The "ruach" of God so when we speak, filled with the Holy Spirit, there is the same power that created the earth and raised the dead. By word Jesus called Lazarus out of the grave!  Ephesians tells us that the word of God is now a vital weapon in the mission to bring His kingdom.  We are to, “Take the helmet of salvation and the sword of the Spirit, which is the WORD of God.” See how they are intertwined here, the Spirit and the Word ”For the weapons of our warfare are not carnal, but mighty through God for the pulling down of strongholds”

Because when we speak we make the unseen, seen. Just as God used words to create, we do to.