Grudem defines a miracle as follows:
"A miracle is a less common kind of God's activity in which he arouses people's awe and wonder and bears witness to himself.? He justifies this definition by awe, or amazement in such a way that God bears witness to himself (Systematic Theology, chapter 52).pointing out the deficiencies in other commonly proposed definitions:
"For example, one definition of miracles is "a direct intervention of God in the world.? But this definition assumes a deistic view of God's relationship to the world, in which the world continues on its own and God only intervenes in it occasionally. This is certainly not the biblical view, according to which God makes the rain to fall (Matt. 5:45), causes the grass to grow (Ps. 104:14), and continually carries along all things by his word and power (Heb. 1:3). Another definition of miracles is "a more direct activity of God in the world.? But to talk about a "more direct? working of God suggests that his ordinary providential activity is somehow not 'direct,? and again hints at a sort of deistic removal of God from the world.
Another definition is "God working in the world without using means to bring about the results he wishes.? Yet to speak of God working "without means? leaves us with very few if any miracles in the Bible, for it is hard to think of a miracle that came about with no means at all: in the healing of people, for example, some of the physical properties of the sick person's body were doubtless involved as part of the healing. When Jesus multiplied the loaves and fishes, he at least used the original five loaves and two fishes that were there. When he changed water to wine, he used water and made it become wine. This definition seems to be inadequate.
Yet another definition of miracle is "an exception to a natural law? or "God acting contrary to the laws of nature.? But the phrase 'laws of nature? in popular understanding implies that there are certain qualities inherent in the things that exist, 'laws of nature? which operate independently of God and that God must intervene or "break? these laws in order for a miracle to occur. Once again this definition does not adequately account for the biblical teaching on providence.
Another definition of miracle is, "an event impossible to explain by natural causes.? This definition is inadequate because
(1) it does not include God as the one who brings about the miracle;
(2) it assumes that God does not use some natural causes when he works in an unusual or amazing way, and thus it assumes again that God only occasionally intervenes in the world; and
(3) it will result in a significant minimizing of actual miracles, and an increase in skepticism, since many times when God works in answer to prayer the result is amazing to those who prayed but it is not absolutely impossible to explain by natural causes, especially for a skeptic who simply refuses to see God's hand at work.
Therefore, the original definition given above, where a miracle is simply a less common way of God's working in the world, seems to be preferable and more consistent with the biblical doctrine of God's providence. This definition does not say that a miracle is a different kind of working by God, but only that it is a less common way of God's working, and that it is done so as to arouse people's surprise.