What is the Sunday of the Fulfillment?
What do we mean by "fulfillment?"
What is the Festival of Christ the King?
What is the liturgical color for the last Sunday after Pentecost?
How is the Sunday of the Fulfillment related to the season of Advent?

WHAT IS THE SUNDAY OF THE FULFILLMENT?

The Sunday of the Fulfillment is the last Sunday of the church year.  On this Sunday, the church looks forward to the time when everyone and everything in heaven and on earth will be together under one head, the Lord Jesus Christ (see Ephesians 1:9-10).

WHAT DO WE MEAN BY "FULFILLMENT?"

This festival is a day of  fulfillment in two senses.  It fulfills the liturgical year by bringing it to an end and returns us once again to the season of Advent.  More importantly, it calls on the church to look with vigilance and faithfulness for the second coming of the Lord Jesus to take His redeemed people into heaven.  This is the fulfillment for which all Christians yearn when they pray, Thy Kingdom come.

WHAT IS THE FESTIVAL OF CHRIST THE KING?

In many churches, the Sunday of the Fulfillment is celebrated as the Festival of Christ the King.  The lectionary readings for the last few Sundays after Pentecost center on the biblical teachings concerning the final judgment, end times, and Christ's second coming to usher in the Kingdom of Glory.  This emphasis culminates in the final Sunday of the church year as a celebration of the coming reign of Christ as King of the universe at the end of time.

WHAT IS THE LITURGICAL COLOR FOR THE SUNDAY OF THE FULFILLMENT?

The usual liturgical color for this day is green, the color of spiritual growth.  This is the color for the Time of the Church, the season between Pentecost and Advent.  However, if the Sunday of the Fulfillment is commemorated as the Festival of Christ the King, white, symbolic of the holiness of Christ, is the appropriate liturgical color.

HOW IS THE SUNDAY OF THE FULFILLMENT RELATED TO THE SEASON OF ADVENT?

Advent is a season of preparation as we anticipate the coming of our Lord.  Since the Sunday of the Fulfillment focuses on the longing of every Christian for the coming of Christ's Kingdom, this day is a transitional festival that brings the church to the first Sunday of Advent, the theme of which is the second coming of Christ.  This watchful longing is summarized in the appointed prayer for the Sunday of the Fulfillment:

Lord God, heavenly Father,
Send forth Your Son, we pray,
That He may lead home His bride, the Church,
That we, with all the redeemed,
May enter into Your eternal kingdom.
Through Jesus Christ, Your Son, our Lord,
Who lives and reigns with you and the Holy Spirit,
One God, now and forever.  Amen.

SOURCES

Preparing for His Return, an article from the web site of the LCMS Commission on Worship.

Ready and Waiting:  The Last Sundays of the Church Year, an article from the web site of the LCMS Commission on Worship.

Jonathon Krenz, Last Sunday of the Church Year / Sunday of the Fulfillment (B), a sermon from Cruce Tectum. 

Jonathon Krenz, Last Sunday of the Church Year / Sunday of the Fulfillment (C), a sermon from Cruce Tectum.