(1) The idea of watchfulness is for one to be cautious of his deeds and matters, namely, contemplating and watching over his deeds and ways whether they are good or evil; not abandoning his soul to the danger of destruction, G-d forbid, and not walking through the course of habit like a blind man in darkness.
(2) Reason certainly obligates this. For after a person has knowledge and reason to save himself and escape from the destruction of his soul, how is it conceivable that he would willingly blind his eyes from saving himself?!
(3) There is certainly no debasement and foolishness worse than this. One who does this is lower than beasts and wild animals whose nature it is to protect themselves, escaping and fleeing from whatever seems harmful to them.
(4) One who walks along in his world without contemplating whether his ways are good or evil is similar to a blind man walking on the bank of a river. His danger is certainly very great and his calamity is more likely than his escape. For negligence in guarding oneself from danger due to natural blindness and negligence due to willful blindness, namely shutting one's eyes by choice and desire is one and the same.
(5) Jeremiah would bemoan on the evil of his contemporaries' affliction with the disease of this trait. They would turn a blind eye to their deeds, not putting heart to consider what they were doing, whether to do or refrain from doing it.
(6) Regarding them he said: "no man regrets of his evil, saying, What have I done? Each one running to his own course, as the horse rushes into the battle." (Jer. 8:6)
(7) The explanation is that they would pursue and go by the momentum of habit and conduct, without leaving themselves time to consider their deeds and ways. Thus they fell into evil without even seeing it.
(8) In truth, this is one of the cunning strategies of the evil inclination, to relentlessly burden people's hearts with his service so as to leave them no room to reflect and consider which road they are taking.
(9) For he knows that if they were to put their ways to heart even the slightest bit, certainly they would immediately begin to feel regret for their deeds. The remorse would go and intensify within them until they would abandon the sin completely.
(10) This is similar to the wicked Pharaoh's advice saying "intensify the men's labor..." (Ex. 5:9). His intention was to leave them no time whatsoever to oppose him or plot against him. He strove to confound their hearts of all reflection by means of the constant, incessant labor.
(11) This is precisely the ploy employed by the evil inclination on human beings. For he is a skilled warrior, expert in the art of cunning. It is impossible to escape from him without great wisdom and far-reaching vision. This is what the prophet screamed out "give heed to your ways!" (Chagai 1:7).
(12) And as Shlomo in his wisdom said: "Give not sleep to your eyes, nor slumber to your eyelids. Save yourself as a deer from the hand of the hunter and as a bird from the hand of the fowler" (Prov. 6:4).
(13) And our sages of blessed memory said "whoever scrutinizes his ways in this world merits to see the salvation of the holy One blessed be He".
(14) And it is obvious that even if one is watchful over himself, it is not within his power to save himself without the help of the holy One blessed be He. For the evil inclination is enormously powerful as scripture says: "the wicked watches the righteous, and seeks to slay him, G-d will not forsake him to his power" (Ps. 37:32).
(15) If a man is watchful over himself, then the holy One blessed be He helps him and he will be saved from the evil inclination.
(16) But if he is not watchful over himself, the Holy One, blessed be He, will certainly not watch over him. For if he gives no heed to himself, who should give heed to him? This is as our Sages of blessed memory have said: "it is forbidden to pity anyone who has no knowledge" (Berachot 33a), and this is the meaning of what they said: "if I am not for myself, who will be for me?" (Avot 1:14).