Whether all acts of virtue are prescribed by the natural law?

Objections

Objection 1 : It would seem that not all acts of virtue are prescribed by the natural law. Because, as stated above (Question [90], Article [2]) it is essential to a law that it be ordained to the common good. But some acts of virtue are ordained to the private good of the individual, as is evident especially in regards to acts of temperance. Therefore not all acts of virtue are the subject of natural law.
Objection 2 : Further, every sin is opposed to some virtuous act. If therefore all acts of virtue are prescribed by the natural law, it seems to follow that all sins are against nature: whereas this applies to certain special sins.
Objection 3 : Further, those things which are according to nature are common to all. But acts of virtue are not common to all: since a thing is virtuous in one, and vicious in another. Therefore not all acts of virtue are prescribed by the natural law.