Here is a quote about St John of the Cross who was a master of the Via Triplex :
"At the beginning of the prologue of The Ascent of Mount Carmel St John writes: "The dark night, through which the soul passes on its way to the divine light of the perfect union of the love of God, so far as it is possible in this life, requires for its explanation greater experience and light of knowledge than I possess. For so great are the trials, and so profound the darkness, spiritual as well as corporal, through which souls must pass if they will attain to perfection, that no human learning can explain them, nor experience describe them. He only who has passed through them can know them." The branch which God trims or prunes is not only a living but a conscious branch. To know the nature of this pruning, which is similar to that of a tree, one must have experienced it. Each one must carry his cross, and only after having borne it with love does he know clearly what the cross is.
Not without suffering indeed, is complete victory obtained over egoism, sensuality, laziness, impatience, jealousy, envy, injustice in judgment, self-love, foolish pretensions, and also self-seeking in piety, the immoderate desire of consolations, intellectual and spiritual pride, all that is opposed to the spirit of faith and to confidence in God, that a man may succeed in loving the Lord perfectly, with his whole heart, with his whole soul, with all his strength, and with all his mind, and his neighbor (enemies included) as himself.(14) Great firmness, patience, and longanimity are also needed to persevere in charity, whatever may happen, when the words of the Apostle are verified: "And all that will live godly in Christ Jesus shall suffer persecution." (15)
We should not, therefore, be surprised that, when St. John of the Cross describes the road which leads most surely and most rapidly to the full perfection of Christian life, he declares that a soul could not reach it without undergoing the passive purification of the senses, which, in his opinion, marks the entrance into the illuminative way, and the passive purification of the spirit, which is at the threshold of the unitive way (if one understands the unitive way not in a diminished form, but according to its full normal development in the servants of God whom the Church proposes as models).
To show that the active purification which we impose on our
selves does not suffice, St. John writes: "For, after all the efforts of the soul, it cannot by any exertion of its own actively purify itself so as to be in the slightest degree fit for the divine union of perfection in the love of God, if God Himself does not take it into His own hands, and purify it in the fire, dark to the soul, in the way I am going to explain." (16) This statement shows clearly the necessity of
the cross, which is affirmed by the Gospel and by all Christian spirituality. We use here, and do so throughout this work, deliberately simple but entirely traditional terms, in order to avoid all exaggeration.
The same master says: "Souls begin to enter the dark (passive) night when God is drawing them out of the state of beginners, which is that of those who meditate on the spiritual road, and is leading them into that of proficients, the state of contemplatives, that, having passed through it, they may arrive at the state of the perfect, which is that of the divine union with God." (17)
First of all, the soul is weaned from sensible consolations, which are useful for a time but become an obstacle when sought for themselves. Whence the necessity of the passive purification of the senses, which places the soul in sensible aridity and leads it to a spiritual life that is much more freed from the senses, the imagination, and reasoning. At this point the soul receives, through the gifts of the Holy Ghost, an intuitive knowledge which, despite a painful obscurity, initiates the soul profoundly into the things of God. At times this knowledge makes us penetrate them more deeply in an instant than would meditation over a period of months and years. To resist temptations against chastity or patience -temptations which present themselves rather frequently in this night of the senses there are required at times heroic acts of chastity and patience, which are, however, extremely fruitful.
In the night of the senses there is a striking light and shade. The sensible appetites are cast into obscurity and dryness by the disappearance of sensible graces on which the soul dwelt with an egoistical complacency. But in the midst of this obscurity, the higher faculties begin to be illumined by the light of life, which goes beyond reasoned meditation and leads to a loving and prolonged gaze upon God during prayer.
After treating of this purification, St. John of the Cross says: "The soul began to set out on the way of the spirit, the way of beginners and proficients, which is also called the illuminative way, or the way of infused contemplation." (18) This text is among the most important in all the writings of St. John of the Cross. Farther on we shall consider it again, and see its meaning and import more clearly.
But even after this purification, that the soul may be freed from the defects of proficients, from the subtle pride which subsists in them, another purification, that of the spirit, is needed.(19) This purification is found in far more advanced souls which ardently desire goodness, but which have too strong a desire that good be done by them or in their way. They must be purified from every human attachment to their judgment, to their excessively personal manner of seeing, willing, acting, from every human attachment to the good works to which they devote themselves. This purification, if
well borne in the midst of temptations against the three theological virtues, will increase tenfold their faith, their confidence in God, and their love of God and neighbor."
http://www.christianperfection.info/tta22.php#bk1
It's a Catholic source but they also have truth mixed with error and true saints in the past (who were persecuted by them).
My own view is that Wesley was attempting to reform Protestantism, but wanting to keep the framework. As is the way of reformations, it was only partial. He had not attained the stage of Unity so could not preach it like Fox did. He did meet a few who were in Union and he had some disagreements with them.