"Now you should know that the outward man may be undergoing trials, although the inward man is quite free from them and immovable. Even in Christ there were an outward man and an inward man, and also in our Lady. Whatever Christ and our Lady ever said of outward things was spoken by the outer man, and the inner man dwelt in immovable detachment. It was thus that Christ said: 'My heart is sorrowful even unto death.' And however much our Lady lamented and whatever other things she said, she was always in her inmost heart in immovable detachment."This is explained, a little, in The Radiance of Being where I talk about the inner spark of the soul, or spirit, that connects us each to God. But Eckhart makes it very practical when he uses another analogy: that of a door and its hinge.
"A door opens and shuts on a hinge. Now if I compare the outer boards of the door with the outward man, I can compare the hinge with the inner man. When the door opens and closes the outer boards move to and fro, but the hinge remains immovable in one place and it is not changes at all as a result."To find in ourselves this detachment, even in the midst of suffering, is not merely a trick for escaping pain for a few minutes – into the eye of the storm, so to speak. It is to become open to God's will, to allow God to work in us, so that we can be one with God and – yes – ultimately share his eternal bliss. But God cannot work in us "unless he finds readiness or creates it". And mostly we are busily giving the powers of our soul over to the outward man and the five senses. "Know then that God expects every religious man to love him with all the powers of his soul. Hence he said: 'Love thy God with all thy heart.'" This is another way of reading the First Commandment, and Matthew 22:37. One way of getting started is described here.
Quotations are from Meister Eckhart, Selected Treatises and Sermons. The illustration shows the Eckhart door in Erfurt Cathedral.