If the Flood narrative is understood literalistically then we are confronted with a vengeful, wrathful, merciless and incompetent tyrant of a god who destroys the whole world in a fit of pique, expressing sorrow for having created humanity and the animals in the first place; even if, at the end of the story, he does redeem himself to some extent by repenting of his monstrous act of carnage and making a covenant with humanity and the animals, of which the rainbow is the sign. But how can such a god be reconciled with the God of love revealed in Christ in the New Testament?
Most biblical scholars believe that the Flood narrative was composed -- whether by reworking Mesopotamian Flood myths or by reworking a Jewish tradition (or, of course, a combination of the two) -- during the Babylonian Exile of the Jews (6th century BC). If this is so, literally (as opposed to literalistically) interpreted the story was most likely intended as an allegory of the destruction of Jerusalem and the Temple, the ending of the Davidic line of kings and the exile of the people to Babylon. In the Ancient world, cataclysmic floods are often used as metaphors or symbols for great social calamities. Noah and his family would, then, represent the righteous remnant of the Jewish people.
That the destruction of Jerusalem and the Exile were indeed likened to the destruction of cosmic order and a return to primordial chaos is confirmed by the prophet Jeremiah (Jeremiah 4:23-26). And here one must recall that prior to God’s first act of creation, ‘Let there be light’ (Genesis 1:3), ‘The earth was without form and void, and darkness was upon the face of the deep; and the spirit of God was moving over the face of the waters’ (Genesis 1:2).
So interpreted, the Flood narrative is an allegory of hope, which tells of God’s loving protection of His people, despite the appalling calamity which has befallen them. It is an allegory designed to reassure and bring comfort to the people, as they ‘lay down and wept’ by the waters of Babylon (Psalm 137:1 / 136 LXX), that out of the chaos to which their world has been reduced God would create a new order. It was at this very period of Jewish history, scholars have pointed out, that the Jews ceased to think of their God, Yahweh, as one amongst many gods, even if the most powerful, and proclaimed Him as the one and only, omniscient and all-merciful, God.