IN 1985, Susan Compton staged an exhibition of the then nonagenarian artist Marc Chagall (1887-1985) at the Royal Academy, and later in Philadelphia. It proved immensely popular, and was due to close in London on 31 March. When the artist died at his home in France at Saint-Paul-de-Vence on 28 March, it became known that one of his last wishes had been for the RA to extend the exhibition for one day, the proceeds to be given to the Ethiopian Relief Fund. It was a typically humanitarian gesture by a man who had been born into a devoutly religious Hasidic Jewish family, at Vitebsk.

As I visited the current exhibition at Albert Dock in Liverpool, the news that Chagall's fellow-countrymen in his native Russia are among those committed to arming the government forces in Syria was very much on my mind. Would the Tate extend the exhibition for a day to raise funds for Syrian refugees and for victims of the appalling killings there? What would Chagall have them do?

There are some who love Chagall; others find his mischievous compositions simple and dull beyond measure. A generation after his death, he remains popular, with a recent exhibition in Paris at the Musée de Luxembourg, and the vibrant Ben Uri exhibition "Chagall, Soutine and the School of Paris", now at Manchester Jewish Museum (until 24 November).

In one of the 1985 obituaries, William Feaver noted that "Folksiness was the basis of his appeal." Writing in The Observer the day before the RA exhibition closed, Feaver perceptively noted a recurrent problem that a "sweet sentimentality crept into his work and, as his fame and popularity increased, the paintings began to represent not the world he had experienced but a world of fond imaginings". For me, the more wistful the later works become, the less engaging I can find them.

The Paris exhibition was broadly staged chronologically, which helped me to see that, as long as Chagall separated his toying with religious symbols from the dream world of the inter-war years, his pictures do have a certain naïve appeal. Once he becomes formulaic, my interest stops. Unlike Picasso or Titian, who, of course, lived as long, his work soon begins to become too much of a production line.

The Liverpool show avoids this problem of perception by restricting itself to a close examination of Chagall's early work, although oddly a final room is staged as a sort of "What Katy did next", with six later works from 1923 to 1967. Although he reached the age of 97 and was productive to the end (again like Titian and Picasso), this exhibition of some 70 works concentrates on the second decade of the 20th century. The Manchester show similarly examines the artists who worked in Paris in the first two decades of the 20th century.

This is, therefore, about an artist who had left the provincialism of Belarus for the cosmopolitan Tsarist world of St Petersburg, in 1906. He later claimed in his autobiography: "Without even knowing that there was such a place as Paris, I found a miniature Europe in (Léon) Bakst's school." He followed his paintbrush to Paris, leaving behind his fiancée, Bella. In the spring of 1911, he found Cubism and the Modernist style of the Ballets Russes all the rage.

One of his grandchildren has said that she does not recall his ever being overtly Jewish, never frequenting the synagogue, lighting the menorah, or sitting down for a sabbath meal. But she may not have been old enough to hear him speaking Yiddish, which was his first language.

He never lost the cultural baggage of his Jewishness, even if his vocabulary became remarkably universalist very early on. As he explained, in 1958, "If a painter is Jewish and paints life, how can there help being Jewish elements in his work! But if he is a good painter, there will be more than that. The Jewish element will be there but his art will tend to approach the universal."

So, as early as 1910, he had produced an image of the resurrection of Lazarus (Philadelphia), and in 1912 he was painting the scene at Calvary, showing Golgotha (now at MoMA, New York) at the Salon in the autumn. As late as 1918, after his wartime return to Russia, he was still signing his pictures in Hebrew, as the intimate scene of rabbis disputing a text (The Study) showed, in Paris.

Liverpool Tate shows, however, this essential strand of Chagall's work, and demonstrates his affectionate recollection of his Hasidic roots. One of his first Parisian works on paper is the struggle between Cain and Abel (private collection). The red earthy brown background is almost that of an African landscape, while both figures tense in fevered altercation; Abel wears a laurel-wreath crown as if to signify innocent virtue.

Alongside it, The Awakening (1910-11) has a reclining figure beneath a vaulted canopy. More William Blake than anything else, the figure arches backwards while God's firmament is above, realised in a single sweep of blue gouache.

And it is already in colour that one begins to sense the liberation that he further explored in Paris. The startling beauty of his 1911-12 Still Life (Utsunomiya Museum of Art, Japan) takes it a long way from Cézanne, from whose tables he has stolen both the pitcher and the apples. The oil lamp and hand-decorated teacup bring back a Russia that we see again in the samovar that is almost the only stable element in the painting

The Soldier Drinks (Solomon R. Guggenheim Museum, New York). This recalls the soldier billeted in the Chagall house during the Russo-Japanese war of 1904-05.

At a glance, the ink-on-paper drawing The Departure for War (1914) is as profound a reflection on loss and foreboding as any Italian or German Renaissance painting of Christ Takes Leave of His Mother. His Homage to Apollinaire (1911-12) takes some getting used to, as Adam and Eve, Siamese twins already in the act of becoming, are set against a clock face; but the smaller sketch for the enormous canvas (2 × 1.895m) makes it easier to understand how Chagall saw creation.

The opportunity of his first solo exhibition took him to Berlin in May 1914, from where he returned home. The outbreak of war prolonged an intended three-month summer visit to eight years. These form the rest of the exhibition, which reflects on the Paris years in the context of Russia before and after the Revolution.

Chagall married his beloved Bella in 1915, celebrating the joy of homecoming, as Maeterlinck does in his 1914 play The Bluebird, in a painting of himself with her in a violet dress (The Promenade, The State Museum, St Petersburg). It looks for all the world as if she is a kite, tethered to one hand while in the other he holds the oiseau bleu.

Flying figures are a common-place in his increasingly visionary painting, whether in the Wandering Jew above the Orthodox cathedral domes of Vitebsk (Over Vitebsk, 1922) or in the figure of Music, one of the wall panels from the decoration for the State Jewish Chamber Theatre in Moscow (1920), which is really the culmination of this remarkably wide-ranging exhibition.

The four panels with the long mural Introduction to the Jewish Theatre (1920), which measures 2.84 × 7.87m, have been exceptionally loaned from the Tretyakov Gallery, Moscow. These reflect on the links between drama and faith, not just in the artist's mind, but in our world.

Fortunately, these works survived the destruction of the theatre, but it was not until 1953 that Chagall was able to sign them. Sadly, the earlier mural commission from the Society for the Encouragement of Jewish Art in Petrograd (1916) was cut short by the Revolution. We only glimpse what it might have been in his liberating sketch for Purim.

This exhibition was seen earlier this year in the Kunsthaus in Zurich, and is brilliantly curated by Simonetta Fraquelli. The views from the gallery over the roofs and docks below are certainly in keeping with much of Chagall's vision of the world. Sadly, peace remains as elusive now as it did throughout his long life.

"Chagall: Modern Master" is at Tate Liverpool, Albert Dock, Liverpool Waterfront, until 6 October. Phone 0151 702 7400. www.tate.org.uk