"And Hashem spoke to Moshe, saying, Speak to all the community of the Children of Israel and say to them: You shall be holy, for I, Hashem your G-d, am holy." (Vayikra 19:2)
How can a human being, who has a physical body and earthly desires, become "holy"?
At Mount Sinai, Hashem gave the Torah to the entire Jewish Nation and conferred the status of KedushatYisrael upon us. This means that He implanted a unique and permanent holiness into every Jewish soul.
Whenever a person is tempted to act in a way that is against the Torah and he controls himself, he elevates himself spiritually and fulfills the mitzvah of "You shall be holy." Since his control is a fulfillment of this mitzvah, he is rewarded, just as Hashem rewards him for all the other mitzvot that he performs. He ascends to a higher spiritual level than he was on before.
Now you might think that just because you withhold yourself from sinning, you aren't really "holy" and this verse does not refer to you. But it does. The verse says, "Speak toall the Children of Israel and say to them, "You shall be holy..." The Torah is teaching us that holiness is not exclusively reserved for tzaddikim, but for any Jew who attempts to elevate himself. (Ohr HaChaim)
This is an incredible concept! Control of our eyes is not just an inner battle between desire and restraint. We master ourselves countless times during the day and therefore, in Hashem's Eyes, we have the highest status - we are holy!
In fact, every time we succeed, we increase our own personal sanctity as well as that of the entire world. Once we understand this concept, we have the method and the motivation to gain control of our eyes. When we internalize the idea that we are holy in Hashem's Eyes, we feel happy with ourselves and we feel inspired to reach for higher levels in Torah and mitzvot.
Today: Each time you control your eyes from looking at an improper sight, tell yourself, "I am a member of a holy nation."