The American Church Dictionary and Cycopedia
The Fifth Sunday in Lent is so called because on this day our Lord began to make open prediction of His sufferings, and in her round of worship the Church begins the solemn commemoration of His Passion and Death. (See LENT, SUNDAYS IN.)
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Miller, William James. Entry for 'Passion Sunday'. The American Church Dictionary and Cyclopedia. https://www.studylight.org/dictionaries/eng/acd/p/passion-sunday.html. 1901.