Before all other important things, therefore, the Sabbath is an expression of the eschatological principle on which the life of humanity has been constructed…The Sabbath brings this principle of the eschatological structure of history to bear upon the mind of man after a symbolical and a typical fashion. It teaches its lesson through the rhythmical succession of six days of labour and one ensuing day of rest in each successive week. Man is reminded in this way that life is not an aimless existence, that a goal lies beyond. This was true before, and apart from, redemption. The eschatological is an older strand in revelation than the soteric, (Biblical Theology, p. 140).The structure of the Christian week begins with the Sabbath, because the work needed for entering into the Sabbath has been completed by Christ. Now, as a result, the church gathers on the first day of the week for worship, fellowship and rest so that we are reminded that this life is lived out of the rest accomplished for us. But it also structures our lives so that we see that in our living out of our rest--it is headed somewhere.
Tomorrow we have the privilege of a grand foretaste of what is already ours in Christ and what has been at the heart of God's creative and recreative activities. The Sabbath, and that heavenly fellowship to which it points, are not after thoughts in God's mind and intentions. Before God created and redeemed, he existed as the Trinitarian God, Father, Son and Holy Spirit, in which he was self-existent and enjoyed the fullness of his own fellowship. He created, though, and created in order to bring his church into that fellowship. That is why he created and that is what tomorrow points to and anticipates. It is not something that God decided to do only after man fell into sin--tomorrow is a foretaste of God's original intentions.
Heaven and eternal fellowship between the triune God and the church is, therefore, what should structure our enjoyment of the day for what it is. Tomorrow is a day of worship, fellowship, and rest that restructures our lives in this world to be lived in light of the world to come, in which, the enjoyment of that world intrudes into our lives here and now.