I won't echo what's been said already, but I will point out that Biblical morality doesn't seem to square with natural law as Feser describes it. Feser writes,
For the same reason, not every human intervention in the natural order counts as "unnatural." Putting eyeglasses on doesn’t "interfere with nature" in a sense that traditional natural law theory would take exception to, because what glasses do is remedy a defect that keeps eyes from performing their natural function. The point of glasses is not to interfere with an organ’s performance of its natural function, but rather to aid it in performing that function. By contrast, the point of birth control devices is to stop an organ from performing its natural function. So such devices do "interfere with nature" in a sense that is illicit from the traditional natural law point of view.
I propose one example to disrupt the harmony between this and Biblical morality: the eunuch.
Jesus's words in Matthew 19:11-12 (KJV):
Jesus replied, "For there are some eunuchs, which were so born from their mother's womb: and there are some eunuchs, which were made eunuchs of men: and there be eunuchs, which have made themselves eunuchs for the kingdom of heaven's sake. He that is able to receive it, let him receive it."
If anything would be unnatural and contradictory to the function of sex, it would be castration, the severest form of male birth control. Yet it is approved by Jesus, perhaps echoing the text of Isaiah 56:4-5, which affirms that eunuchs have a special place in God's heart.
For this is what the LORD says:
"To the eunuchs who keep my Sabbaths,
who choose what pleases me
and hold fast to my covenant-
to them I will give within my temple and its walls
a memorial and a name
better than sons and daughters;
I will give them an everlasting name
that will not be cut off.
Eunuchs, who cannot further their "name"--their progeny--are promised a name that will not be "cut off." Rather scintillating word play.
But compare the contradictory passage at Deuteronomy 23, wherein eunuchs--along with illegitimate children, Ammonites, and Moabites, sorry--are forbidden from entering "the assembly of the LORD."
The Catholic prohibition of self-sterilization, begun at the first Council of Nicaea and defended in Paul VI's Humanae Vitae, obviously takes the Deuteronomist position against Jesus's own words and Isaiah's promise.
"[W]e must once again declare that the direct interruption of the generative process already begun, and, above all, directly willed and procured abortion, even if for therapeutic reasons, are to be absolutely excluded as licit means of regulating birth. Equally to be excluded, as the teaching authority of the Church has frequently declared, is direct sterilization, whether perpetual or temporary, whether of the man or of the woman."
Anyone care to reconcile the contradiction?