whose mind is stayed on Thee’ (Isaiah 26:3)
Yes, God---pure Be-ing or existence--is the one form-less, essence-less, self-existent, self-knowing, self-giving, absolute, indestructible, and abundant existence that forever takes form, that is, incarnates, as you, me, and everything else, but which is never even for a moment absorbed by the innumerable objects of its Self-expression. In other words, God---if you choose to use the word at all---is the life that is the subject of true existence, the very life that lies within, and otherwise manifests itself through and as objects, being all persons and things---the very livingness, or rather Self-livingness, of life itself. Put perhaps more simply, you are I AM in expression---as you. In the words of the renowned Unity minister and author Eric Butterworth, you are an 'eachness' within the ALL-ness of God. Yes, 'Thou art That.' Whether or not you are aware of it, you are divine and one with this 'God-ness,' being the point---and just one of an infinite number of such points---at which the Great I AM reproduces and experiences Itself. Amazing!
Now, if you want perfect peace in your mind, then keep your mind ‘stayed’ in the Eternal Now, that is, in the medium in which all things live, move, and have their being. Keep your mind grounded in the consciousness of the moment, from one moment to the next. For me, mindfulness is the best form of prayer and meditation. It is the primary means by which I stay grounded in the Eternal Now---God, if you like. You don't need to believe in someone else’s concept of God---not even mine, for heaven’s sake. You don't need to use the word God, or think in theistic terms, at all. All you have to do is to stay mindfully aware of, and alert to, the content (both internal and external) of the present moment at all times or at least as much and as often as you can. Angels---assuming there are any---can do no better.
And how do you know when you are living mindfully? The answer is simple---you are living mindfully when you are no longer fretting about or fighting the past, or fearing the future. You are able to accept, with calm contentment and total equanimity, whatever is. Perfect peace, just like perfect love, drives out all fear, anxiety, anger, and resentment (cf 1 Jn 4:18). Indeed, there is simply no room in a mindset of perfect peace for any negative thoughts or emotions.