It cannot be limited to prayers and other forms of service alone that we feel our closeness to God and bask in His glory - but always.
For one who conducts himself as a mundane person throughout the day, and his soul is buried beneath the trivialities and frivolities of his pursuits - ultimately his prayers and service will be mundane as well, unable to arouse his soul even at the times that he does serve God.
Rather, all day, in every thing he does, one has to be a Jew! Throughout the day, one has to feel his closeness to God - sometimes on a higher level, sometimes on a lesser level - but a Jew always!
Many times, we believe that we can compartmentalize our lives; we don't allow our family life to mix with our business/school/yeshiva dealings, we won't bring our work home, and we leave our Judaism in shul or the beis medrash. Reb Kalonymos Kalman is telling us - at least regarding that last item - that it can't be that way.
The mistaken idea that it is possible to be a Jew at home and anything else on the street is a dangerous one; it leads to an eventuality in which our specifically Jewish activities are affected negatively. As a matter of fact, that exact sentiment - echoed by Russian maskil Judah Leib Gordon - is often the first step toward shirking one's duties as a God fearing Jew.
The answer is to counter this problem by remembering that no matter where we find ourselves, we are first and foremost Jews, and we should be proud of that special role that we have been chosen to fill. It should inform every action of the day and permeate our lifestyle at all levels.
There is no such thing as "a simple Jew" - even the "simplest" Jew is capable of the most incredible achievements known to man. We would do well to remember that.