"The pope prays for all Arabic speakers. May God bless you all!" the pope said in Arabic at the audience, after a bishop read out an Arabic translation of the pope's comments praising the results of the Second Vatican Council.
The landmark Council, which began 50 years ago this week, is a "compass" for the Catholic Church "in the middle of the storms", the pope said.
As a young reformer, the then Joseph Ratzinger took part in the Council, better known as Vatican II, which revolutionised Catholic rituals.
The Council brought together 2,250 bishops and lasted from 1962 until 1965.
The pope has always defended the 15 "constitutions" adopted by the Council despite complaints from traditionalists in the Church over several reforms.