We can't really see the light from our efforts in mitzvot right now because of the veil that covers it, but when Moshiach is here, we will see the light of the efforts we have made.

It is like building windows in the night. Sometimes we are privileged to get a glimpse of starlight or even moonlight, but the "interior" of our world still seems so dark despite our efforts. It's only when the day comes that we will really see and understand why the work was so important.