IF HE were alive today, Moses might well think that modern methods of religious communication would make his task easier. Instead of having to barge into Pharoah’s court and risk arrest, he could simply thunder out a blog on the internet, or plague Egyptian software with a religious bug that left behind the message: “Let my people go”. But would the message of an electronic Moses have the same authority as his Old Testament avatar?

Such speculations might be on Jewish minds shortly as we celebrate the festival of Passover, the pivotal moment in Jewish history when the Exodus not only became the world’s first national liberation movement but also led to the revelation at Mount Sinai, whose reverberations are still felt by Christians and Muslims too.

But what of the Israelites themselves? They were famously stiff-necked and needed as much persuading of Moses’s credentials as Pharoah did. Would it have been any better for them to have received the word of God via the internet and might that have proved a more effective medium? The answer is not at all certain, for they would have found themselves subject to so many competing messages from other would-be prophets that they might have followed someone else to an entirely different Promised Land or else decided to junk all religious directives and stay put by the Nile. And that is very much the problem which we face today.

Modern googlers face an immense number of religious sites but have the added problem of deciding their true provenance. Which websites are informative and which manipulative? Which are based on accumulated insights tested down the centuries and which are the sudden fruit of individual megolamania? Three kinds of religious website are particularly distasteful: the pernicious, the misleading and the honeytrap.

The problem with the pernicious sites is not that they simply spew out religious hatred but that they cloak their vileness in an aura of scientific objectivity that can ensnare the unwary into taking their claims seriously. One site (whose name I shall certainly not publicise) awards itself the impressive subtitle of “An Educational Forum for the Examination of Religious Truth and Religious Tolerance”. In reality, it is exactly the opposite and uses neither truth nor tolerance, but engages in a full-scale attack on Judaism, both ancient and modern.

It even has the gall — maybe I should annoy its authors and say that it has the chutzpah — to declare: “This website is inspired by Rabbi Professor Jonathan Sacks, Chief Rabbi of the British Commonwealth . . . We are dedicated to bringing about understanding between people of different faiths.” It would be more accurate to say that the website was inspired by hatred of Jonathan Sacks and that it sought to prevent mutual understanding. The second problem with religions websites concerns material quoted correctly but out of context, so that it is misleading. There are occasions when this is unintentional, but very often it is deliberate. Thus another website cites the Talmudic saying that “if a Jew is tempted to do evil, he should go to a city where he is not known and do evil there”.

This is adduced to show how Judaism apparently encourages wickedness, but it completely fails to explain that this quotation refers specifically to using prostitutes and ignores the long discussion about how one should avoid the temptations of the flesh, but that if a person feels totally unable to resist, then he should do so elsewhere — partly because this way he does not disgrace his family, and partly in the hope that the journey will cool his ardour.

The honeytrap is the cleverest and most deceptive website. It is epitomised by one site which proclaims its purpose to be helping Jews to fend off missionary activity. It invites readers to delve into New Testament texts to arm themselves against attempts to undermine their faith, but then gradually suggests that there is some truth in them after all and that a Jew will find true fulfilment in accepting Jesus as Lord.

In some respects the problem is as old as Moses, for even in his time the Israelites were assailed by false prophets, claiming to speak in God’s name but offering a false message. Deuteronomy breaks off from proclaiming the Commandments to warn of the “dreamer of dreams” (xiii: 2), while Jeremiah lambasts those who tell “lies in My name” (xxiii: 25).

In essence, the difficulty then and now is: who can you trust? How do you know if what you are hearing preached or reading online is to be believed? Deuteronomy suggests a dual approach: first, decide if the new teaching corresponds to truths already given or is a departure from them (xiii: 6). Does it enhance existing faith or jettison it? This assumes that one already has firm religious foundations against which to judge new ideas, and leaves vulnerable those who live in a religious vacuum but are searching for meaning. It is all the more important for them to employ the second test: “Then shalt thou inquire, and make search and ask diligently” (xiii: 14) and thoroughly check the facts of what one is being told, its source, context and reliablility.

Of course, there is also much that is excellent on the internet, with instant availability of information, texts and contacts, that helps inquirers and aids scholars. Wariness of the pitfalls should not prevent enjoyment of the glories.

As Jews sit down to the Passover meal and remember the freedom cry first uttered by Moses, this traditional ritual is being complemented by fast-moving technical developments. Many will first download Passover recipes, songs and children’s games.

Religious life today is no longer just a case of “Go tell it on the mountain” but also of “Go look it up on Google” — but with a religious health warning of “handle with care”.

Rabbi Dr Jonathan Romain is minister of Maidenhead Synagogue and author of Reform Judaism and Modernity (SCM)