It is a common misconception that if a man takes the first step in faith, so to speak, and prays a prayer of some kind that he is saved and a new life has begun. This is sometimes called "percentage theology’ or "percentage salvation" meaning that, even though very small, man has a part in his salvation. But this passage in Ephesians makes it clear that that is just impossible. God initiates it – it is a gift. And, left to himself in his sin, man would never choose God. Verse one above states that man is dead - dead men cannot make decisions. Hence, it is the work of God, regeneration precedes faith.
Moreover, we see how just how special and the great import of this doctrine. God chose his people before the foundations of the earth (Eph. 1:4). We should not take this lightly.