Here is a prayer appropriate for Labor Day, from the pen of 16th-century church reformer John Calvin:
My God, Father and Savior, since you have commanded us to work in order to meet our needs, sanctify our labor that it may bring nourishment to our souls as well as to our bodies.
Make us constantly aware that our efforts are worthless unless guided by your light and by your hand.
Make us faithful to the particular tasks for which you have bestowed upon us the necessary gifts, taking from us any envy or jealousy at the vocations of others.
Give us a good heart to supply the needs of the poor, saving [us] from any desire to exalt ourselves over those who receive our bounty.
And if you should call us into greater poverty than we humanly desire, save us from any spirit of defiance or resentment, but rather let us graciously and humbly receive the bounty of others.
Above all, may every temporal grace be matched by spiritual grace, that in both body and soul we may live to your glory.
(From a collection of prayers Calvin wrote for the people of Geneva, Switzerland. This translation is from 2000 Years of Prayer, Morehouse Publishing, 1999.)