Now the question arises what is sanctification, since it has so lofty a rank. Thou shouldest know that real sanctification consists in this that the spirit remain as immovable and unaffected by all impact of love or hate, joy or sorrow, honour or shame, as a huge mountain is unstirred by a gentle breeze. This immovable sanctification causes man to attain the nearest likeness to God that he is capable of. God’s very essence consists of His immovable sanctity; thence springs His glory and unity and impassibility. If a man is to become as like God as a creature may, that must be by sanctification. It is this which draws men upward to glory, and from glory to unity, and from unity to impassibility, and effects a resemblance between God and men. The chief agent in this is grace, because grace draws men from the transitory and purifies them from the earthly. And thou shouldest know that to be empty of all creature’s love is to be full of God, and to be full of creature-love is to be empty of God. – From his sixth sermon
I am not a Wesley scholar, nor will I pretend to be. Instead, I will say that from what I’ve read and the little work that I’ve done on Wesley and the East, I see in Eckhart a synergism of the two. (Or maybe Wesley pulled a lot from Eckhart who mirrored the East in several ways.) At the very least, both see sanctification as something not attained to immediately but a process.