Psalms 19:1-14
God has revealed Himself successively by a twofold witness: firstly, in His creation (vv. 1-6), whose silent but so eloquent language makes known to the ends of the earth His power and His wisdom (Acts 14:17). The sun’s regular and health-giving course, beaming its light and warmth on all the world is a constant proof of the goodness of God towards all His creatures (Psalms 136:8; Matthew 5:45).
The second witness is by His Word (vv. 7, 11). Holy, just and good, spiritual, even when it is only concerned with the Law given to Israel (Romans 7:12; Romans 7:14), of still how much greater value is it now that it is complete! This excellent Word warns the servant (v. 11) and reaches his conscience (which constitutes within every man a third witness). It brings to light as many hidden faults (committed inadvertently: v. 12) as wilful sins, committed in self-will, the result of self-esteem or pride (see this distinction in Numbers 15:27-30).
We also find that a three-fold witness at the beginning of the Epistle to the Romans: creation (Romans 1:20), conscience (Romans 2:15) and the Law (Romans 2:17 . . .) is set before man to light his condition and lead him to salvation.