Charles Spurgeon Commentary Genesis 7:6

"And Noah was six hundred years old when the flood of waters was upon the earth." — Genesis 7:6 (ASV)

He was nearly five hundred years old when he began to preach about the flood — a good old age to take up such a subject. For a hundred and twenty years he pursued his theme — three times as long as most men are ever able to preach — and now at last God's time of long-suffering is over, and he proves the truthfulness of the testimony of his servant by sending the flood that Noah had foretold.