During much of Ordinary Time this year, we will listen to readings from the gospel according to Mark. For Sundays we have three years worth of readings. Year A is comprised mostly of Matthew; Year B, Mark; and Year C; Luke. Parts of John are proclaimed during the Easter Season, and on other feast days and occasions across the three-year cycle.
It has not always been this way, however. For a long time the same readings were proclaimed every year. In the first half of the 20th century, biblical scholarship began to develop once again in the Church. This was reflected in the proceedings at the Second Vatican Council, which began fifty years ago this October. The Council’s Constitution on the Sacred Liturgy spoke of the importance of scripture in liturgical celebrations, and called for the larger, more extensive collection of readings we use today.
Sacred scripture is of the greatest importance in the celebration of the liturgy. For it is from scripture that lessons are read and explained in the homily, and psalms are sung; the prayers, collects, and liturgical songs are scriptural in their inspiration and their force, and it is from the scriptures that actions and signs derive their meaning. Thus to achieve the restoration, progress, and adaptation of the sacred liturgy, it is essential to promote that warm and living love for scripture to which the venerable tradition of both eastern and western rites gives testimony… In sacred celebrations there is to be more reading from holy scripture, and it is to be more varied and suitable. (Constitution on the Sacred Liturgy, no. 24, 35)