Objection 1. It seems that five expressions of will--namely, prohibition, precept, counsel, operation, and permission--are not rightly assigned to the divine will. For the same things that God bids us do by His precept or counsel, these He sometimes operates in us, and the same things that He prohibits, these He sometimes permits. They ought not therefore to be enumerated as distinct.
Objection 2. Further, God works nothing unless He wills it, as the Scripture says (Wisdom 11:26). But the will of expression is distinct from the will of good pleasure. Therefore operation ought not to be comprehended in the will of expression.
Objection 3. Further, operation and permission appertain to all creatures in common, since God works in them all, and permits some action in them all. But precept, counsel, and prohibition belong to rational creatures only. Therefore they do not come rightly under one division, not being of one order.
Objection 4. Further, evil happens in more ways than good, since "good happens in one way, but evil in all kinds of ways," as declared by the Philosopher (Ethic. ii, 6), and Dionysius (Div. Nom. iv, 22). It is not right therefore to assign one expression only in the case of evil--namely, prohibition--and two--namely, counsel and precept--in the case of good.
I answer that, By these signs we name the expression of will by which we are accustomed to show that we will something. A man may show that he wills something, either by himself or by means of another. He may show it by himself, by doing something either directly, or indirectly and accidentally. He shows it directly when he works in his own person; in that way the expression of his will is his own working. He shows it indirectly, by not hindering the doing of a thing; for what removes an impediment is called an accidental mover. In this respect the expression is called permission. He declares his will by means of another when he orders another to perform a work, either by insisting upon it as necessary by precept, and by prohibiting its contrary; or by persuasion, which is a part of counsel. Since in these ways the will of man makes itself known, the same five are sometimes denominated with regard to the divine will, as the expression of that will. That precept, counsel, and prohibition are called the will of God is clear from the words of Matthew 6:10: "Thy will be done on earth as it is in heaven." That permission and operation are called the will of God is clear from Augustine (Enchiridion 95), who says: "Nothing is done, unless the Almighty wills it to be done, either by permitting it, or by actually doing it."
Or it may be said that permission and operation refer to present time, permission being with respect to evil, operation with regard to good. Whilst as to future time, prohibition is in respect to evil, precept to good that is necessary and counsel to good that is of supererogation.
Reply to Objection 1. There is nothing to prevent anyone declaring his will about the same matter in different ways; thus we find many words that mean the same thing. Hence there is not reason why the same thing should not be the subject of precept, operation, and counsel; or of prohibition or permission.
Reply to Objection 2. As God may by metaphor be said to will what by His will, properly speaking, He wills not; so He may by metaphor be said to will what He does, properly speaking, will. Hence there is nothing to prevent the same thing being the object of the will of good pleasure, and of the will of expression. But operation is always the same as the will of good pleasure; while precept and counsel are not; both because the former regards the present, and the two latter the future; and because the former is of itself the effect of the will; the latter its effect as fulfilled by means of another.
Reply to Objection 3. Rational creatures are masters of their own acts; and for this reason certain special expressions of the divine will are assigned to their acts, inasmuch as God ordains rational creatures to act voluntarily and of themselves. Other creatures act only as moved by the divine operation; therefore only operation and permission are concerned with these.
Reply to Objection 4. All evil of sin, though happening in many ways, agrees in being out of harmony with the divine will. Hence with regard to evil, only one expression is assigned, that of prohibition. On the other hand, good stands in various relations to the divine goodness, since there are good deeds without which we cannot attain to the fruition of that goodness, and these are the subject of precept; and there are others by which we attain to it more perfectly, and these are the subject of counsel. Or it may be said that counsel is not only concerned with the obtaining of greater good; but also with the avoiding of lesser evils.
Source: Summa Theologica (New Advent)