He also praised the "welcoming hearts" of the Lebanese people in accepting both Christian and Muslim families fleeing from conflict in neighbouring Syria.
In a country of 4.4 million people, refugees now compromise almost 25 per cent of the nation's population.
Francis made the comments during a meeting at the Vatican with delegates from the Maronite Catholic Church in Lebanon.
He thanked the country for "maintaining a creative balance, as strong as the cedar tree," between Christians and Muslims.
In a light-hearted remark, the Catholic leader compared the influx with the "multiplication of the loaves", because more families had arrived in Lebanon than he had expected.
Some 6.3 million people affected by ongoing unrest in Syria have been internally displaced.
According to the Pew Research Centre, only Turkey has accepted more Syrian refugees than Lebanon (3.4 million).
But the Human Rights Watch organisation has warned the vast majority of Syrian refugees in Lebanon lack legal status - limiting their rights to travel and work, as well as their access to healthcare and education.
According to the Vatican, the Maronite Catholic Church boasts 3.5 million members - with the majority in the Middle East and the Americas.
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