Heidelberg Catechism, Lord’s Day 38
Heidelberg's answer is outstanding, and was probably the single most informative answer I encountered when I first read it. Mainly, the Lord's Day is for the gospel, rest, the church, the Bible, the sacraments, prayer and the poor (which, by the by, would make an excellent basis for a liturgy). But there is also an eschatological dimension to the Sabbath, in that by resting from sin and allowing God to work in our lives, we enter the eternal rest that we have coming. Beautiful.]
Q103. What is God’s will for you
in the fourth commandment?
that the gospel ministry and education for it be maintained,
and that, especially on the festive day of rest,
I diligently attend the assembly of God’s people
to learn what God’s Word teaches,
to participate in the sacraments,
to pray to God publicly,
and to bring Christian offerings for the poor.
that every day of my life
I rest from my evil ways,
let the Lord work in me through his Spirit,
and so begin in this life
the eternal Sabbath.