The Divrei Chaim zt'l teaches: A doctor can diagnose an illness by looking into his patient's eyes, and then he knows how to treat the disease. Similarly, by looking at the Chanukah lecht, one can attain a spiritual refuah for all ailments of his neshamah.
We say, לראותם אלא בהם להשתמש רשות לנו ואין. The Divrei Chaim translates these words as, “We don’t have permission to use the lecht, only via looking at them." This indicates that looking at the Chanukah lecht is how we use them. This is because by looking at the lecht, we achieve spiritual purity and growth.
The Nesivos Shalom zt'l (Chanukah p.85) explained the pasuk (Tehillim 30:6) באפו רגע כי, "For His wrath lasts but a moment," that באפו is gematria חנוכה (as is written in the holy sefarim). The pasuk is saying באפו רגע כי, that on Chanukah, one can attain purity in a moment. It is very hard to correct one's bad deeds and destructive habits, but by looking intently at the Chanukah lecht, everything can be rectified in a moment.
This is also alluded to in the pasuk (Tehillim 91:8) תראה רשעים ושלמת תביט בעיניך רק, "You will but gaze with your eyes, and you will see the annihilation of the wicked." By merely gazing at the Chanukah lecht, שלמת, one attains sheleimus, perfection, רשעים, in all areas where he is lacking and still considered a rasha.
The Nesivos Shalom says, "When a Yid says the brachos on the Chanukah lecht and looks at them and accepts on himself that from now on he won't return to his foolish ways, with the strength of Chanukah, this is sufficient to rectify everything in just one moment."
