Leonard Cohen, whose fifth yahrzeit was last month, was deeply connected to his Jewish roots. Although he spent much of his time in a Buddhist monastery in California, and was even ordained as a Buddhist monk, we only need to listen to his songs and poetry to appreciate just how much he knew of his Jewish heritage and how important it was to him.

He once explained to an interviewer that there was no conflict between Buddhism and Judaism because in Buddhism “there is no prayerful worship and no discussion of a deity”.

Leonard Cohen grew up in a prominent, prosperous and communally active Montreal family. His great grandfather Eliezer Cohen, who had been given a rabbinic semicha in Lithuania, went into business once he moved to Canada. He changed his name to Lazarus, established a brass foundry and twice served as president of Montreal’s Sha’ar Hashomayim synagogue. His brother Tzvi Hirsch, Leonard’s great-uncle, remained in the rabbinate and became Canada’s unofficial chief rabbi.

Leonard’s grandfather Lyon continued the family’s leadership tradition; he founded Canada’s first Jewish newspaper, built a community centre, set up a fund to help the victims of Russian pogroms to settle in Canada and capped his career by becoming president of the Canadian Jewish Congress.

On his mother’s side, Leonard’s grandfather, Rabbi Solomon Klonitzky-Kline, had been the head of a yeshiva in Kovno before emigrating to the USA. There he wrote scholarly books on midrash and Hebrew grammar. Leonard Cohen spoke of how he came to live with them in Canada as an old man, and how he and his grandfather studied together.

So Leonard Cohen grew up at the heart of the Montreal Jewish community. But in his late twenties he fell out with them very badly. He had begun to make a name for himself as a poet and was invited to give a speech at the community’s library. One of Cohen’s role models, A M Klein, the community’s leading poet and intellectual, had recently suffered a nervous breakdown, effectively bringing his literary career to an end. Cohen blamed the Jewish community. He told members that Klein’s breakdown was their fault, that their indifference to artists, their attention to business rather than scholarship and learning had effectively exiled Klein, leaving him isolated and unsupported. In a passionate speech, he condemned the community’s religious practices as fossilised and lacking in spirituality, accusing them of distorting the idea of God.

Cohen effectively gave up on the Montreal Jewish community. But he did not give up his affinity to his Judaism. Few of his songs are as Jewish as Who By Fire, based on the Rosh Hashanah liturgy, but a little more humorous and citing modern rather than ancient ways of meeting one’s demise. We only have to listen to Cohen’s poems and lyrics to realise just how much he knew of the Bible, and how familiar he was with stories and ideas from the Talmud and Kabbalah. The outstanding example is his song Hallelujah, into which he feeds images from the Books of Judges, Kings and Psalms, the Talmud and the Zohar.

Hallelujah opens with King David playing a secret chord on his harp which wins him divine favour. It is Cohen’s loose interpretation of the midrash in which David wakes every midnight to play his harp and compose songs of praise to the Almighty. He follows this with another Talmudic legend in which David asks God to test him, to prove that he was as upright as the Patriarchs. God, knowing David’s weaknesses, tempts him into adultery with Bath Sheba, whom he sees bathing from his rooftop. According to the Bible, David’s adultery and his subsequent sin of having her husband killed in battle brought havoc to his kingdom. In Cohen’s words, it broke his throne.

Cohen introduced King David into the song because of the word Hallelujah. Although it is a word we know well, it only occurs in the Book of Psalms written, according to rabbinic tradition, by King David. Words, Cohen tells us, can be holy or broken. God used words to create the world. Words are also profane, we use them to curse and abuse. But Hallelujah, he seems to be telling us, is not like other words. He ends his song by singing that even if everything goes wrong, even at the worst of times, we can still say “Hallelujah”.

Cohen read a lot of mystical literature. He once said that one of the great themes of kabbalistic thought is the idea of “repairing the face of God”. He was referring to the kabbalistic legend about a cosmic catastrophe at the moment of creation. The divine energy which connects heaven and earth was being poured into vessels. But the energy was too strong for the vessels. They broke and heavenly sparks fell to earth, where they became trapped beneath the fragments of the broken vessels that landed on top of them. The idea behind the legend is that only by elevating the sparks can we repair the world. Fortunately, he tells us in his song Anthem, “there is a crack in everything; that’s how the light gets in”. It is probably his most famous line and Leonard Cohen said that Anthem was probably the best song he had ever written; it drew the whole of his life’s work together.

Anthem is a kabbalistic song. But The Window, which he recorded in 1979, is even more esoteric. It is a song about the mystical ascent of a soul to heaven and Cohen draws heavily both on the Zohar, the primary text of kabbalah, and on the bizarre and mysterious Book of Revelation with which the Christian Bible concludes. Apart from its profound mysticism, the song illustrates one of the most intriguing things about Cohen’s work: his tendency to merge Christian and Jewish ideas without any apparent division between them. Even though he came from a learned Jewish family, he said that the Montreal in which he grew up was rich in Christian influences, which he saw as “the great missionary arm of Judaism”. In his song Different Sides, he sings that although the two religions appear different to us, in the eye of heaven they are one and the same. His song The Story of Isaac, in which he relates the sacrifice episode in the Bible, contains allusions to the church’s communion ritual. And the story he tells in The Butcher, a song which castigates God for allowing the Shoah, takes place at a scene which reminds us strongly of the crucifixion.

Leonard Cohens’s most dramatic fusion of Christian and Jewish themes must be You Want It Darker, a song he wrote at the end of his life, when he knew he was dying. He recites the first line of the Kaddish in English, follows it with a line about the crucifixion and then delivers a short eulogy to the victims of the Shoah. And leaves us in no doubt that he is a Jew. Knowing that his death is not far off, he repeats the word that Abraham used when he was commanded to sacrifice Isaac. Hineni, he says to God; here I am. He was ready.

Leonard Cohen: The Mystical Roots of Genius by Harry Freedman is published by Bloomsbury Continuum