The Chief Rabbi has come under fire for his opposition to civil marriage for gay and lesbian couples (see our front-page story this week).

Since there is no question of the government forcing religious groups to carry out same-sex weddings, his critics say that Chief Rabbi simply should have kept shtum rather than plunge into a contentious and divisive issue.

However, they overlook an important point. It is true that the commandments of the Torah are binding only on Jews. However, according to Orthodox theology, there are basic standards of morality which apply to all humanity known as the Seven Noahide Laws.

One of the Noahide prohibitions is sexual immorality. Needless to say, rabbis differ over precisely what falls within the bracket of the Noahide commandments: some take it to mean the arayot, the set of forbidden sexual relationships detailed in Leviticus, including of course that against male homosexual unions.

As Dayan Yisroel Lichtenstein, head of the Federation Beth Din, has observed, the Talmud says that one of the things for which the nations of the world were praised was that they did not write a ketubah – marriage contract – for two males: in other words, they did not legitimise gay marriage.

The last Lubavitcher Rebbe was among those who encouraged Noahide observance. It arose from an understanding that when Jews have the opportunity to influence the values of wider society, they should take it.

This was hardly possible when our forebears were confined behind ghetto walls. But the situation in a modern Western democracy is entirely different, especially when there are several minyans-worth of Jewish peers in the House of Lords, among them the Chief Rabbi. If one of the country’s most prominent religious figures had not said anything – in contrast to the Church leaders – people would have wondered why.

There is a countervailing view in Jewish tradition: you don’t offer moral guidance when it will fall on deaf ears and even more so when it might risk a backlash (in this instance from secular atheists against what they see as illiberal religion).

But even if the Chief Rabbi and the United Synagogue had decided not to take a public position, he would still have had to explain the rationale behind his decision – in particular to those within the Orthodox world who would have expected him to speak out. Saying nothing was not an option.