Ned B. Stonehouse quoting J. Gresham Machen in the biographical-memoir J. Gresham Machen:

Instead of stifling the pleasures afforded by the acquisition of knowledge or by the appreciation of what is beautiful, let us accept these pleasures as the gifts of a heavenly Father. Instead of obliterating the distinction between the Kingdom and the world, or on the other hand withdrawing from the world into a sort of modernized intellectual monasticism, let us go forth joyfully, enthusiastically to make the world subject to God [underline CCS] (187).

Machen got it right: Christians need to be joyful and enthusiastic as they make the world subject to God, i.e., as they fulfill the Great Commission.