Are the precepts of the Decalogue set down in an appropriate way?

It seems that the precepts of the Decalogue are not set down (tradantur) in an appropriate way:

Objection 1:  The affirmative precepts order one toward acts of the virtues, whereas the negative precepts draw one back from acts of the vices.  But with respect to any subject matter whatsoever, there are virtues and vices opposed to one another.  Therefore, in any subject matter about which a precept of the Decalogue gives direction, there should have been both an affirmative precept and a negative precept.  Therefore, it is inappropriate for there to be affirmative precepts for some subject matters and negative precepts for others.

Objection 2:  Isidore says that every law is based on reason.  But all the precepts of the Decalogue belong to divine law.  Therefore, a reason should have been given for each of the precepts, and not just for the first and third.

Objection 3:  Through the observance of the precepts one merits rewards from God.  But God’s promises have to do with the rewards attached to the precepts.  Therefore, a promise should have been made in each of the precepts, and not just in the first and the fourth.

Objection 4:  The Old Law is called the ‘law of fear’, because it was through threats of punishment that it induced men to observe the precepts.  But all the precepts of the Decalogue belong to the Old Law.  Therefore, a threat of punishment should have been made in each of the precepts, and not just in the first and the second.

Objection 5:  All the precepts of God should be retained in memory; for Proverbs 3:3 says, “Write them on the tablets of your heart.”  Therefore, it was inappropriate for a mention of memory to be made in just the third precept.  And so it seems that the precepts of the Decalogue were inappropriately set down.

But contrary to this:  Wisdom 11:21 says, “You have ordered all things in measure, and number, and weight.”  Therefore, a fortiori, He has preserved an appropriate mode of setting down the precepts of His law.

I respond:  The highest wisdom is contained in the precepts of divine law; hence, Deuteronomy 4:6 says, “This is your wisdom, and understanding in the sight of nations.”  But it is the role of wisdom to dispose of all things in a fitting manner and order.  And so it ought to be clear that the precepts of the Law have been set down in an appropriate way.

Reply to objection 1:  The negation of one of two opposites always follows from the affirmation of the other, but it is not always the case that the affirmation of one of two opposites follows from the negation of the other.  For instance,‘If something is white, then it is not black’ is valid, but ‘If something is not black, then it is white’ is not valid.  For the negation extends to more things than the affirmation does.  Hence, it is likewise the case that ‘One should not do harm’, which is a negative precept, extends to more persons as a primary dictate of reason than does ‘One ought to give obedience (or benefits) to someone’.
However, it is a dictate of reason in the first instance that one ought to give obedience (or benefits) to those from whom he has received benefits, as long as he has not yet repaid them.  But, as Ethics 8 says, there are two beings in return for whose benefits no one can make sufficient repayment, viz., God and his father.  And this is why there are only two affirmative precepts, one having to do with honoring one’s parents and the other having to do with the celebration of the Sabbath in commemoration of God’s favors.

Reply to objection 2:  The precepts that are purely moral have an obvious reason behind them, and so there was no need for a reason to be added to them.
However, some precepts are such that either a ceremonial precept or the specification of a moral precept is added to them.  For instance, in the first precept there is the addition of “You shall not make graven images,” and in the third precept the day of the Sabbath is specified.  And this is why a reason had to be given in these two cases.

Reply to objection 3:  Men order their acts for the most part toward some sort of usefulness.  And so the promise of a reward had to be attached to those precepts from which no usefulness seemed to follow or by which some sort of usefulness was impeded.  Now since parents are already in their receding years, no usefulness is expected from them.  And  so a promise is attached to the precept about honoring one’s parents.  The same holds for the precept that prohibits idolatry.  For this precept seems to impede the apparent usefulness which men believe they can attain by entering into a pact with the demons.

Reply to objection 4:  As Ethics 10 says, punishments are especially necessary for those who are prone to evil.  And so a threat of punishment is added only to those precepts in which there was a tendency toward evil.
Now men were prone to idolatry because of the general practice of the Gentiles.  Similarly, there were also men prone to perjury because of the frequency of oaths.  This is why a threat is attached to the first two precepts.

Reply to objection 5:  The precept about the Sabbath is posited as a commemoration of a past favor, and this is why it contains a specific mention of memory.
An alternative reply is that the precept about the Sabbath has adjoined to it a specification that does not belong to the law of nature, and that is why this precept requires a special admonition.