Ante-Nicene Fathers, Vol IX:
Epistle to Gregory and Origen's Commentary on the Gospel of John.: Chapter XXVIII

28.  Christ as Life.

It is clear also that the principle of that life which is pure and unmixed with any other element, resides in Him who is the first-born of all creation, taking from which those who have a share in Christ live the life which is true life, while all those who are thought to live apart from this, as they have not the true light, have not the true life either.