Adoration of the Shepherds, Murillo [Web Gallery of Art]
The Solemnity of the Nativity of the Lord has four different Mass formularies, each with its own prayer and readings. Any of the four fulfills our obligation to attend Mass. These are:
Vigil Mass, celebrated 'either before or after First Vespers (Evening Prayer) of the Nativity'; that means starting between 5pm and 7pm.
Mass During the Night, known before as 'Midnight Mass'.
Mass at Dawn.
Mass During the Day.
When you click on 'Readings' below from the New American Bible you will find links to the readings for each of the four Masses. The readings from the Jerusalem Bible for the four Masses are all on one page.
Readings (New American Bible: Philippines, USA)
Readings (Jerusalem Bible: Australia, England & Wales, India [optional], Ireland, New Zealand, Pakistan, Scotland, South Africa)
Gospel (Mass During the Day) John 1:1-18 (New Revised Standard Version, Anglicised Catholic Edition)
In the beginning was the Word, and the Word was with God, and the Word was God.