8. This is the meaning of St. Paul's affirmation: "I live, now not I, but Christ lives in me" Gal.2:20. In saying, I live, now not I, he meant that, even though he had life it was not his, because he was transformed in Christ, and it was divine more than human. He consequently asserts that he does not live, but that Christ lives in him. In accord with this likeness and transformation, we can say that his life and Christ's were one life through union of love. This transformation into divine life will be effected perfectly in heaven, in all those who merit the vision of God. Transformed in God, these blessed souls will live the life of God and not their own life-although, indeed, it will be their own life, because God's life will be theirs. They they will truly proclaim: We live, now not we, but God lives in us.
Although transformation in this life can be what it was in St. Paul, it still cannot be perfect and complete, even though the soul reaches such transformation of love as is found in the spiritual marriage, the highest state attainable in this life. Everything can be called a sketch of love in comparison with that perfect image, the transformation in glory. Yet the attainment of such a sketch of transformation in this life is a great blessing, for with this transformation the Beloved is very pleased. Desiring the bride to put Him as a sketch in her soul, He said in the Canticle: Put Me as a seal upon your heart, as a seal upon your arm.[Ct.8:6] The heart signifies the soul in which God dwells in this life as a seal, which is the sketch of faith, mentioned above; the arm signifies the strong will in which He is present as the seal, which is the sketch of love we just discussed.
9. The soul's state at this time is such that I do not want to neglect saying something about it, even though briefly, regardless of the fact that it is indescribable. It seems to the soul that its bodily and spiritual substance is drying up with thirst for this living spring of God. Its thirst is like David's when he said: As the hart longs for the fount of waters, so does my soul long for You, my God. My soul has thirsted for God, the living fount; when shall I see and appear before the face of God? [Psalm 42:2-3]. This thirst so exhausts the soul that she would think nothing of breaking through the midst of the camp of the Philistines, as did David's strong men to fill their containers with water from the cistern of Bethlehem, which was Christ. [1 Par. 11:18] She would consider all the difficulties of the world, and the fury of demons and infernal afflictions nothing if by passing through them she could plunge into the unfathomable spring of love. In this respect it is said in the Canticle: Love is as strong as death and its jealousy as hard as hell. [Ct. 8:6]." St. John of the Cross THE SPIRITUAL CANTICLE Stanza 12