“The heavens declare the glory of God, and the sky above proclaims his handiwork. Day to day pours out speech, and night to night reveals knowledge. There is no speech, nor are there words, whose voice is not heard.”
Two elements of nature are affirmed in these first three verses: 1) nature says something. This is emphatic: the heavens declare, the sky proclaims, speech is poured out and knowledge is revealed; 2) this revelation is universal in that its speech is discernable. The voice of creation cannot be not heard.
This seems to oppose my position that general revelation cannot interpret itself. How should we understand McGrath in light of Psalm 19 when he writes, “Nature can only exist; it has no mind to interpret, and no tongue to communicate that interpretation” (137).
No tongue to communicate? But Psalm 19 says that it pours out speech, everyday. It is important to note that the remainder of the psalm takes the reader to meditate upon the particular revelation of the LORD in his word—his law, testimony, precepts, commandment, fear, and rules (vv. 7-10). The delight of the David is this testimony (v. 10, cf. Ps. 1:1-2). I think that such an emphasis and delight implies that the revelation of nature is subordinate to the word of God. Moreover, the passage even highlights the primacy of particular revelation by founding this particular revelation to be of the God who is supreme over all creation. David’s recognition of God in the natural world (i.e. Psalm 19:1-6) is the result of God illumining his mind by (and as) the inspired Holy Scripture (cf. Acts 4:25; 2 Peter 2:21; 2 Tim 3:16).
 Calvin writes, “Yet, in the first place, wherever you cast your eyes, there is no spot in the universe wherein you cannot discern at least some sparks of his glory. You cannot in one glance survey this most vast and beautiful system of the universe, in its wide expanse, without being completely overwhelmed by the boundless force of its brightness” (I.V.1).