This helps us understand well the words of the Goan in his chapter on The Mystery of the [Hebrew] Letters, that during the period of the ingathering of the exiles, the Sitra Achra will become stronger (comments of the copyist: in Likutei Hagra the secret of the Letters, p. 40, the commentary Beer Yitzchak brings the Gaons comment that the verse: the redeemed of the Lord will return refers to Mashiach ben Yosef who is the first redeemer, through whose agency the ingathering of exiles will be accomplished. Then, during the footsteps of the Mashiach, the Sitra Achra will be most powerful). The main desire of the Sitra Achra is to uproot the truth, and this is what is meant by the verse: Esau hates Jacob, because Jacob is in the line of truth, as is written give Truth to Jacob. The Sitra Achra knows that the goal is redemption of the truth and sanctification of God. which occur along with the ingathering of the exiles and rebuilding Jerusalem as explained above. The Sitra Achra also knows that as the footsteps of the Mashiach progress, so the end of the power of impurity nears. He therefore girds himself with all his strength and power to wage his battle to uproot the truth and every good deed that leads to sanctification of God.
We can thus understand what our Sages meant by their comments on the footsteps of the Mashiach (Sota, 49b) where the Talmud states: during the footsteps of the Mashiach, truth will be missing and brazenness will be blatant, a son will disgrace his father, and the young will shame the elders. Why will all this occur, especially during the footsteps of the Mashiach more or than in another period? For the redemption of the truth and sanctification of God are the goals of the redemption along with the ingathering of the exiles and the rebuilding of Jerusalem. Therefore, during the footsteps of the Mashiach the Sitra Achra exerts himself more powerfully in his war to root out the truth. The word missing -- the truth will be missing means that it will have been uprooted according to the order of the Hebrew alphabet [this means that the order is : first is the first letter, then the last letter, then the second letter, then the next to the last letter, etc.] According to that order, the of the word can be exchanged for . Thus during the final footsteps of the Mashiach, the amount of ingratitude and requiting evil for good will become greater than ever since the creation of the world.
The term during the footsteps of the Mashiach, which is used by our Sages, should be interpreted literally: during the time of the footsteps of the Mashiach and at its high point, i.e., at the height of the activities at the beginning of the Redemption primarily the ingathering of the exiles, rebuilding Jerusalem, redemption of Truth and sanctification of Gods name, as noted above--during this time the Sitra Achra will become more powerful in attempting to disturb and precipitate failure by uprooting the truth and preventing sanctification of God. This is what is meant by who taunted the footsteps of Your Mashiach [Ps. 89:52]
How strong is the force of the Sitra Achra that he managed to hide from the eyes of our holy forefathers the danger of the klipot layers: from the eyes of our forefather Abraham, the klipa of Ismael; from the eyes of our forefather Isaac, the klipa of Esau; and from the eyes of our forefather Jacob, the klipa of the terafim. During the footsteps of the Mashiach, the Sitra Achra becomes even stronger, in order to strike Biblical scholars with blindness.
All this is obligatory upon us to know and understand beforehand, when we carry out our holy work of gathering in the exiles and rebuilding Jerusalem. We must know beforehand that to the extent that this holy work will increase--so the Sitra Achras power to disturb and bring about failure will increase with his primary weapon which is eradicating the truth as explained above by our Sages and the Gaon. If we know all this ahead of time-- the Sitra Achras desire and the force of his warfare, then we will know how to deal with it practically. We will know how to fight him, measure for measure. That is, the Sitra Achra wishes to uproot Truth and to bring about desecration of God name, and we will fight him by redemption of the truth and sanctification of God-s name. This is also what is meant by the verse: God wages war against Amalek from generation to generation [Ex. 17:16]. The forces of Gods seal is that truth will give us the strength as we proceed step by step in our war. We must remember that this power comes miraculously from Heaven according to our Sages (Sanhedrin 64a); in the incident when a note fell from Heaven, they state that truth was written on it, which is the seal of God. But in every commandment the awakening from below is required. About this it says the truth will sprout from the land [Ps. 85:12]. When we act on behalf of redemption of Truth from below, then God will aid us with His imprint, and since the main center of the Sitra Achra is in the gates of Jerusalem, as it says come to its gates; cast lots on Jerusalem (Ovadia 1:11), and as it states: sin crouches at the entrance against the entrance to the city of Jerusalem, because all the desire of the impure force is to attach itself to the center of Holiness.
It says about this: God will denounce you O Satan...He who chooses Jerusalem [Zach. 3:2]. Therefore here at the gates of the holy city of Jerusalem, may it be built and established, is the site and center for the supreme force to counterattack the angel of Esau who fights to uproot the truth.