Does the Old Law contain just one precept ?

It seems that the Old Law contains only one precept (praeceptum):

Objection 1:  As was established above (q. 92, a. 2), a law is nothing other than a precept.  But the Old Law is a single law.  Therefore, it contains only one precept.

Objection 2:  In Romans 13:9 the Apostle says, “If there is any other commandment, it is comprised in this word:  ‘You shall love your neighbor as yourself’.”  But this is a single commandment (mandatum).  Therefore, the Old Law contains only one commandment.

Objection 3:  Matthew 7:12 says, “All things whatsoever you would that men should do to you, do you also to them; for this is the Law and the prophets.”  But the whole of the Old Law is contained in the Law and the prophets.  Therefore, the whole of the Old Law contains just one precept.

But contrary to this:  In Ephesians 2:15 the Apostle says, “.....  making void the Law of commandments contained in decrees.”  And he is talking about the Old Law, as is clear from the Gloss on this same passage.  Therefore, the Old Law contains many commandments within itself.

I respond:  Since a precept of the law is obligatory, it has to do with something that ought to be done.  But the fact that something ought to be done stems from its being necessary for some end.  Hence, it is clearly part of the notion of a precept that it implies an ordering to an end—viz., insofar as what is commanded is necessary or expedient for that end.
Now it is possible for a single end to be such that many things are necessary or expedient for it.  Accordingly, precepts can be given with respect to different things insofar as they are ordered to a single end.  Hence, one should claim that (a) all the precepts of the Old Law are one insofar as they are ordered to a single end, and yet that (b) they are many because of the diversity of the things that are ordered to that end.

Reply to objection 1:  The Old Law is called a single law because it is ordered to a single end, and yet it contains diverse precepts because of the distinction among the things that are ordered to that end.  Similarly, the art of building is a single art because of the oneness of its end, since it aims at building a house; and yet it contains diverse precepts because of the diversity of the acts that are ordered to this end.

Reply to objection 2:  As the Apostle says in 1 Timothy 1:5, “The goal of the precept is charity.”  For every law aims at establishing the friendship either of men with one another or of man with God.  And so the whole of the Law is fulfilled in the single commandment, “You shall love your neighbor as yourself,” taken as the goal of all the commandments.  For the love of God is also included in the love of neighbor when the neighbor is loved because of God.  Hence, the Apostle used this one precept in place of the two precepts which have to do with the love of God and the love of neighbor and about which Our Lord says in Matthew 22:40, “On these two commandments depend the whole Law and the prophets.”

Reply to objection 3:  As Ethics 9 puts it, “The friendly acts directed toward another proceed from the friendly acts that a man directs toward himself,” viz., as long as the man is related to the other in the same way that he is related to himself.  And so when it says, “All things whatsoever you would that men should do to you, do you also to them,” a certain rule for the love of neighbor, implicitly contained in “You shall love your neighbor as yourself,” is being explicated.  Hence, it is a sort of explication of that commandment.