8:17 multiply upon the earth. This is a repetition of the Edenic command to the created animal kinds (Genesis 1:20, 22). In order to do this, they must migrate from Ararat, each finding its proper ecological niche in the drastically changed and widely varied environments of the post-diluvian world. During the Ice Age following the Flood, land bridges existed across the Bering Strait from Siberia to Alaska and down the Malaysian Strait into New Guinea, facilitating such migrations. Also, Noah’s descendants certainly knew how to build and use boats, and some of the animals may well have been transported in this way, as well as on rafts of vegetation transported out to sea during river floods.

8:19 out of the ark. Here it is again asserted, as clearly as could be expressed, that all the present land animals in the earth have descended from those on the ark.

8:20 offered burnt offerings. Noah thus sacrificed what amounted to one-seventh of his flocks and herds of domestic animals, a real act of thanksgiving and faith on his part. The world was far more forbidding in aspect than when they had entered the ark: rugged and desolate, cold and stormy, barren and silent. It had been purged and cleansed of its wicked and violent inhabitants, however, and God had preserved His remnant through the awful cataclysm, so this was a service of both great praise and earnest petition.

8:21 not again curse. The promise of God, given in response to Noah’s sacrificial prayer of thanksgiving and intercession, is tremendous in scope. He would never again “curse the ground” with a worldwide curse as He had done following Adam’s sin. The Edenic curse is still in effect, of course, but there would be no other. Noah had, indeed, brought “comfort” to the world concerning “the ground which the LORD had cursed” (Genesis 5:29).

8:21 every living thing. Neither would God ever again bring a worldwide cataclysm to the earth as He had with the Flood.

8:22 remaineth. This dual promise would be kept as long as the earth existed in its probationary state, with man still in his sinful condition, his “heart evil from his youth.” Eventually, the earth would be renovated and the curse removed altogether (Revelation 22:3).

8:22 shall not cease. The principle of uniformity is here established by God for the post-Flood world. Not only would the basic laws of nature still continue in effect (these had, of course, operated even during the Flood) but also the regular operation of its natural processes (these had been greatly intensified during the Flood). The basic processes of earth are its rotation on its axis and its orbital revolution around the sun. These control all annual and diurnal processes, which in turn control practically all biological and geological processes. Absolute uniformity of the day/night cycle and the seasonal cycles assures at least general uniformity of functioning (allowing for statistical variations about an average) of other processes. Thus the principle of uniformitarianism is valid absolutely for the laws of nature ever since the imposition of God’s curse (except for special miracles) and is valid statistically for the processes of nature since the flood.