The Baba Sali zt'l once told someone that he knew exactly where he was at that time. The Baba Sali told him the name of the place, and the man admitted that it was so. People were amazed – it was ruach hakodesh – and they asked the Baba Sali how he reached such a level. The Baba Sali replied, "When one guards his eyes from seeing what he shouldn't, his eyes open up to see spirituality."
The taamim (trop) over the words תתורו ולא are גרש אזלא, which can be translated "divorce/banishment go away". This is because the pasuk is discussing guarding the eyes. When one isn't cautious with his eyes, he is banished and divorced from the Shechinah, and even from his own family, as is well known the tragedies that technology causes. When he is cautious with his eyes, גרש אזלא, all these forms of divorce and troubles leave him, and life becomes good for him.
The Ben Ish Chai (introduction to Vaeschanan) discusses the pleasures of three worlds: (1) this world, (2) עדן גן התחתון, the lower Gan Eden, and (3) העליון עדן גן, the pleasures of the upper Gan Eden. He writes that the primary pleasure in this world is food and drink. The primary pleasure of the lower Gan Eden is smell (the good scents that are there). The primary pleasure of the upper Gan Eden is from sight, because in this world, tzaddikim sit and enjoy the glow of the Shechinah.
The human face represents these three worlds and pleasures. There is the mouth, above it, the nose, and even higher are the eyes. The mouth represents the pleasures of this world, which come from the consumption of food and drink. Above the mouth is the nose, representing the pleasure of the lower Gan Eden, the pleasure of smell. Higher are the eyes, which represents the pleasures of Gan Eden Ha'Elyon, the upper Gan Eden, the pleasure of sight.
Reb Shmuel Shapiro zt'l, from the great Breslover chasidim, was extremely cautious with his eyes. (I heard from many special Yidden in Yerushalayim who lived in Reb Shmuel Shapiro's neighborhood, that when they were young, they always saw Reb Shmuel walking with his eyes closed, and they were sure that he was blind r”l.) When he was niftar and they were about to bury Reb Shmuel, Reb Tzvi Cheshen Shlita asked Reb Yaakov Meir Shechter shlita, "What is Reb Shmuel doing now?" Reb Yaakov Meir replied immediately, "Now he is opening his eyes." His eyes were closed his entire life, and now his eyes can open and see the spirituality that he earned from a lifetime of mesirus nefesh to guard his eyes.
B'derech tzachus: In this world, a room is illuminated when one flicks up the light switch. When one turns the light switch down, it becomes dark. As it is known, this world is the exact opposite of the next world. There, it is the opposite. If you turn your head down, it will be light for you. When you raise your eyes, it is dark.
Guarding the Eyes Saves from Troubles
Another benefit of shemiras einayim is that it saves from all troubles. Tikunei Zohar (Tikun 70, p.31a) states, בעיינין וכן בדיבורא תליין דינין כל, "All punishments are because of speech and because of the eyes, as Chazal (Bava Basra 131a) state, רואות שעיניו מה אלא לדיין לו אין." Alluded in these words is that dinim come when people aren't cautious with their eyes.
In contrast, the reward for guarding the eyes is very great. Rabbeinu Yonah (Igeres HaTeshuvah 19:20) teaches, "When a person doesn't raise his eyes, his eyes will merit to see ה' בנועם, the sweetness of Hashem. This is his reward מדה כנגד מדה. As Chazal (Vayikra Rabba 23:13) say, "Whoever turns his eyes down in order not to look at arayos, he will merit to see the Shechinah, as it states (Yeshayahu 33:15) וְעֹצֵם עֵינָיו מֵרְאוֹת בְּרָע, 'He who... closes his eyes from seeing evil,' and it states afterwards (ibid. 33:17) עֵינֶיךָ תֶּחֱזֶינָה מֶלֶךְ בְּיָפְיוֹ, 'The King in His beauty shall your eyes behold.'"
