The whole world was lost. The whole world was corrupt. The whole of Adam's race was degenerate and walked in wickedness, provoking the wrath of God. But God, in great pity, mercy and compassion showed Himself gracious to one man. "Noah found grace in the eyes of the Lord." God spared Noah. God saved Noah. Through him, God preserved His family, preserved our race and thus preserved His elect for all generations to come!
Blessed be His name, God does intervene to save! He does not have to save. No mortal will ever seek salvation from Him until first he is sought by Him. But God has, in indescribable, infinite mercy, chosen to save a people for His own glory and save them, He will!