Shmiras Einayim for Moshiach
HaRav HaMekubal Yosef Shabtei Shani says that one of the key tools for Klal Yisrael to bring Mashiach and build the third and final Beit Hamikdash is Shemirat HaEnayim, guarding our eyes. A person should think: "My eyes are wondrous tools. They are windows to my thoughts, the hands of my mind. I must protect them from harmful sights. I must guard them from evil, I dare not misuse them. Daily, I commit myself to the Torah's command: 'Do not wander after your hearts and your eyes' (Bamidbar 15:39). Daily, I promise to use my eyes for the heavenly, for the holy, for the lofty. My eyes are a gift, and I respect the One who gave them to me. I use His gifts as He wants me to use them.”
Once our eyes have seen something, it is very hard to get that image out of our heads. Many might ask, "Who cares what's in my head, as long as I don't do anything". This is a flawed way of thinking, for Chazal teach us that where a person's mind is, that is where he really is. The author of the Sefer Da Et Atzmecha explains that a person is a combination of both soul and body. The soul is a person's essence and the body is a garment to it. A person's body might be in New York, but his mind - in Israel. Then he is essentially in Israel, even though his body is standing in New York.
The Chidah writes in the name of his grandfather the Chesed L'Avraham that it is possible for a Minyan to omit Tachanun on grounds of a Brit, even though no Brit will happen in that Shul, or even in that city. Neither the father or Sandak are in the Minyan, and the Kise Eliyahu is not there either. He explains that if the majority of the people in the Minyan will be attending a Brit that day, all their minds will be on the Brit, and therefore they would not say Tachanun. We see again that where a person's mind is, that is where he is in essence.
If we are careful and make sure that our eyes only see good, then we will always be in a good place, for our minds will only be thinking good thoughts. In the merit of our Shemirat Enayim, may we see the coming of Mashiach Bekarov.