Before there can be fulfilment, another than Moses must come,
bringing another doctrine. Instead of a law enjoined, there must be
grace and truth revealed. For to enjoin a command and to embody the
truth[2] are two different things; just as teaching and doing differ.
Moses, it is true, teaches the doctrine of the Law, so far as
exposition is concerned, but he can neither fulfil it himself nor
give others the ability to do so. That it might be fulfilled, God's
Son had to come with his fullness; he has fulfilled the Law for
himself and it is he who communicates to our empty heart the power to
attain to the same fullness.
[Footnote 2: Es ist zweirlei, Gesetz geben, und, Wahrheit werden.]
This becomes possible when we receive grace for grace, that is, when
we come to the enjoyment of Christ, and for the sake of him who
enjoys with God fullness of grace, although our own obedience to the
Law is still imperfect. Being possessed of solace and grace, we
receive by his power the Holy Spirit also, so that, instead of
harboring mere empty letters within us, we come to the truth and
begin to fulfil God's Law, in such a way, however, that we draw from
his fullness and drink from that as a fountain.