Worship in the context of Lutheranism is not a focus on what we do but primarily on what God does for us, and then secondly, our response in service to Almighty God in thanksgiving and praise.
Historically the time of gathering for worship was called the Divine Service (and in some churches this terminology is still used), which emphasizes the point that when we gather in worship as followers of Christ we are being served by God.
Within the context of the historic liturgy of the Church, there are times when God descends to meet us with His saving grace - these are Holy Baptism, Holy Communion, Holy Absolution (each of these elements of our gathered time together are considered as being sacraments of the Lutheran Church), and the reading of Holy Scripture.
When instituting the Divine Service, Luther was clear on the importance of retaining much of what had been practiced in the centuries before, while implementing key differences in the theology which accompanied some of these practices.
At the heart of Lutheran worship is a focus on Jesus Christ and His presence in Word and Sacrament. God gathers us for worship to serve us through the reading of his Word, the body and blood of his Son, and the forgiveness of sin through the absolution pronounced to all who repent.
What we pray is what we believe.
This is a simple phrase which comes from the Latin Lex Orlando, Lex Credandi. The basic principle here is that prayer and belief are intrinsically linked. How we worship should reflect what we say we believe, and then lead to how we ultimately live our lives.
This is why, across all of our gatherings, we worship in a way which which focuses on the three key aspects where the Grace of God descends to those gathered, following the same format, and remaining consistent with out theology.
When we gather for worship we follow a simple pattern which allows for flexibility, yet remains constant and is consistent with our theology and practice of worship as a Lutheran congregation.