After exhibiting the harmonious revelation of God's perfections made by His works and His word, the Psalmist prays for conformity to the Divine teaching. (Psa 19:1-14)
the glory of God--is the sum of His perfections (Psa 24:7-10; Rom 1:20).
firmament--another word for "heavens" (Gen 1:8).
handywork--old English for "work of His hands."