“When praying for healing is it scripturely sound to say, ‘speaking it as though it is’? In other words speaking things into existence. I thought only God can speak things into existence.”
This is usually a misunderstanding of (or corruption of) 1 Peter 4:11, “If anyone speaks, they should do so as one who speaks the very words of God.” or other scripture which refers to praying and asking the Father. This passage in 1 Peter is specifically talking about using the gifts of the Spirit remembering that we represent God and “that in all things God may be praised through Jesus Christ.” (1 Peter 4:11)
Usually in the New Testament “speaking” refers to speaking the Gospel, i.e., teaching others and almost always it is a part of a gift of the Spirit. When teaching, we have to remember that we do represent God (“speaks the very words of God”). As such, James warns, “we who teach will be judged more strictly” (James 3:1). The words speak, speaks, and speaking are not used in reference to us saying something and it creates something. That is an invalid extrapolation of scripture.
Jesus did say, “Very truly I tell you, my Father will give you whatever you ask in my name…. Ask and you will receive, and your joy will be complete.” John 16:23-24 This is significantly different from the incorrect teaching that we can just speak and it will be. This is asking the Father and He will answer. Even the misunderstanding of “speaking” has to have the understanding that it is God who does it to have any hope of validity.
John said, “This is the confidence we have in approaching God: that if we ask anything according to his will, he hears us.” (1 John 5:14) The key to asking and having confidence is asking “according to his will”. Scripture is very clear, the Father cares deeply for us and will provide for us. But scripture is also very clear, “When you ask, you do not receive, because you ask with wrong motives, that you may spend what you get on your pleasures.” James 4:3 NIV
To be blunt: there are many who teach “speaking it as though it is” without teaching “speaking according to his will” because they have wrong motives. They desire to have a lot of material things and easy life.
We have been promised just the opposite. When we “speak the very words of God” we are promised persecution Yes, God will provide. Yes, we can have a life abundant. Yes! the Father will give us whatever we ask–according to His will. So let us live with confidence and ask with confidence as we walk with God. He hears us!