Christians often understand the doctrine of the Trinity as if there were three separate divine agents who form a kind of loving troika and as if, when they want to do something in the world, they deliberate as a committee.
But as I argue in my book [Allah: A Christian Response], this is all wrong. It is a bastardized doctrine of the Trinity. Christians who know what they are talking about believe that there is one and only one God who has no associates-- no divine troika, no divine committee of three. The Word and the Spirit are distinct but inseparable from the Speaker of the Word and Breather of the Spirit, and no divine "person"-- neither Father, nor Son, nor the Spirit-- ever acts independently in any activity. The Holy Three who are the Holy One interpenetrate each other in a way that creatures do not. Consequently, you cannot count God in the same way you count things in the world, and of course, you cannot count when it comes to God simply because God is not one of the things to be counted but is a source of all things that can be counted.
The entire interview with Miroslav Volf can be read here.