“But when the fulness of the time came, God sent forth his Son, born of a woman, born under the Law.” Gal.4:4

Because the Law can give us neither justification nor faith, and nature with all its toil can gain us nothing, St. Paul now preaches Him who in our stead has won for us such faith, and who is a master in justification, for justification did not come to us easily, but at great cost, namely, it was paid by God’s own Son. Hence the Apostle writes “when the fulness of the time came,” that is, when the time of our bondage had come to an end.

For God’s ancient people that time was fulfilled with Christ’s advent in the flesh, and in like manner it is still being fulfilled in our daily life, whenever a person is illumined through faith, so that our serfdom and toil under the Law come to an end. For Christ’s advent in the flesh would be useless unless it wrought in us such a spiritual advent of faith. And verily, for this reason He came in the flesh, that He might bring about such an advent in the spirit. For unto all who before or after believed in Him thus coming in the flesh, even to them He is come. Wherefore, in virtue of such faith, to the fathers of old His coming was ever present.

From the beginning of time to the end of the world everything must needs depend upon this coming, this advent, in the flesh, whereby humanity is set free from bondage, whensoever, wheresoever and in whomsoever such faith is wrought. And the fulness of time is come for every person when we begin to believe in Christ as the One whose advent was promised before all times and who has now come.

Martin Luther – 1522