What does the apostle mean?
I think A.W. Tozer gives us a pretty good idea:
"The 'layman' need never think of his humbler task as being inferior to that of his minister. Let every man abide in the calling wherein he is called and his work will be as sacred as the work of the ministry. It is not what a man does that determines whether his work is sacred or secular, it is why he does it. The motive is everything. Let a man sanctify the Lord God in his heart and he can thereafter do no common act. All he does is good and acceptable to God through Jesus Christ. For such a man, living itself will be sacramental and the whole world a sanctuary. His entire life will be a priestly ministration. As he performs his never so simple task he will hear the voice of the seraphim say 'Holy, Holy, Holy, is the Lord of hosts: the whole earth is full of his glory.'" A.W. Tozer The Pursuit of God
Meum cum sim pulvis et cinis