The pontiff urged the faithful to follow the "luminous example" of the two 19th-century sisters and two others, from France and Italy, who were canonised along with them on a sunny spring morning.
Marie Alphonsine Ghattas was born in 1843 in Jerusalem during its rule by the Ottoman Empire, and died there during the British mandate period in 1927.
She was beatified -- the final step before canonisation -- in 2009.
Around 2,000 pilgrims from the Palestinian territories, Israel and Jordan, some waving Palestinian flags, attended the mass as well as Abbas, who had a private audience with the pope yesterday.
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Ghattas, through her focus on women's education and community work, left behind a network of convents, schools and religious centres -- a more palpable legacy than Bawardy, who lives on more through the memory of her tough and mysterious life.
A miracle that led to Ghattas's canonisation was the resuscitation of a Palestinian engineer in 2009, who was electrocuted and suffered a heart attack, but regained consciousness two days later after relatives prayed for her intercession.
During her life, Ghattas is said to have seen the Virgin Mary in several apparitions, and nuns talk of miracles she performed then, including saving a girl who had fallen down a well by tossing her rosary into the water.
The other two new saints are Jeanne-Emilie de Villeneuve (1811-1854) and Maria Cristina dell'Immacolata (1856-1906).
The Vatican said last week it was preparing to sign its first accord with Palestine, two years after recognising it as a state.