The Baal HaSulam writes in his  "Introduction to the Book, Panim Meirot uMasbirot," (Point 8): Our sages have already said, “You have not a generation without such as Abraham, Isaac, and Jacob.” Indeed, that Godly man, our Rav Isaac Luria, troubled and provided us the fullest measure. He did wondrously more than his predecessors, and if I had a tongue that praises, I would praise that day when his wisdom appeared almost as the day when the Torah was given to Israel. There are not enough words to measure his holy work in our favor.

The full method of correction comes to us from the ARI. He put into action everything that earlier Kabbalists had prepared. His soul holds such a unique place in the system of souls that, from his time onward, the Light began to influence all souls, guiding them toward the final correction (Gmar Tikkun).

Before the ARI, spiritual development moved only through the first stages - 0, 1, 2, and 3. But the ARI, through the corrections he made in the system of souls, entered the 4th stage and began shaping Malchut in its complete form. He represents the Sefira Yesod (the last step before Malchut), and this is why he is called Mashiach ben Yosef (Messiah, son of Joseph- where Joseph refers to Yesod). After Yesod, Malchut itself begins its correction.

All the souls before the ARI belonged to the stage of preparation. With him, however, the true awakening of all souls began. Of course, this process spans centuries, but it was the ARI who opened the channel that allows the Light from the earlier stages to pass into the fourth and final stage, where real correction starts.

Mashiach is the revelation of the Light within the system of souls. The Light enters Malchut through Yesod. The ARI opened this gate for the Light, and that is why he is called Mashiach ben Yosef. Messiah here means the power of correction. Through the ARI’s soul, this force began to manifest. By correcting his own soul within the collective system, he enabled the Light to flow into Malchut and act upon all souls.

Now the task falls to us: to prepare our souls for the ascent from Malchut to Bina. This stage is the correction of Malchut, known as Mashiach ben David (Messiah, son of David).