The first instance of confession-prophecy was when the Israelites complained to Moses that God had brought them out of Egypt only to die and not inherit the Promise Land. God responded: So be it; your negative confession shall be a prophecy.
As surely as I live, declares the LORD, I will do to you the very things I heard you say: In this desert your bodies will fall–every one of you twenty years old or more who was counted in the census and who has grumbled against me — Numbers 14:28-29 NIV.
But the principle works both ways. If negative words could lead to bad, positive words would also be honored by God. So in Jesus’ time, if you confessed faith in Jesus, He healed you. The proverbist said: Death and life are in the power of the tongue — Prov. 18:21 KJV.
When you pray today, make a positive confession.