From Life Together:
After the first morning hour, the Christian’s day until evening belongs to work. “People go out to their work and to their labor until the evening” (Ps 104:23). . . . Praying and working are two different things. Prayer should not be hindered by work, but neither should work be hindered by prayer. Just as it was God’s will that human beings should work six days and rest and celebrate before the face of God on the seventh, so it is also God’s will that every day should be marked for the Christian both by prayer and work. Prayer also requires its own time. But the longest part of the day belongs to work. The inseparable unity of both will only become clear when work and prayer each receives its undivided due. Without the burden and labor of the day, prayer is not prayer; and without prayer, work is not work. Only the Christian knows that. Thus it is precisely in the clear distinction between them that their oneness becomes apparent. . . .
The unity of prayer and work, the unity of the day, is found because finding [God] behind the day’s work is what Paul means by his admonition to “pray without ceasing” (1 Thess 5:17). The prayer of the Christian reaches, therefore, beyond the time allocated to it and extends into the midst of the work. It surrounds the whole day, and in so doing, it does not hinder the work; it promotes work, affirms work, gives work great significance and joyfulness. Thus every word, every deed, every piece of work of the Christian becomes a prayer. . . . “And whatever you do, in word or deed, do everything in the name of the Lord Jesus” (Col 3:17).