Genesis 1:4

And God … good This phrase is repeated (Genesis 1:10; Genesis 1:12; Genesis 1:18; Genesis 1:21; Genesis 1:25, and in slightly amplified form, Genesis 1:31) at each successive creative act, except on the second day (Genesis 1:8, where see note). The purpose of this sentence is to express (1) that the phenomena of the natural world, in their respective provinces, fulfil the will of the Creator, (2) that what is in accordance with His will is "good" in His sight.

and God divided … darkness By this simple and concrete expression it is implied, that God assigned their own places to "light" and "darkness" respectively, and that, before the moment of separation, the light had been confused and entangled in the darkness. The two elements were now divided, and apportioned to different dwelling places, cf. Job 38:19 quoted above.