Charles H. Spurgeon on Psalms 90:10

There have been several gradual abbreviations of man's life. Death hath been coming nearer and nearer to us, as you may see in the several ages and periods of the world. Adam, the first of human kind, lived nine hundred and thirty years. And seven or eight hundred years was a usual period of man's life before the Flood. But the Sacred History (which hath the advantage and preeminence of all other histories whatsoever, by reason of its antiquity) acquaints us that immediately after the Flood the years of man's life were shortened by no less than half...After the Flood man's life was apparently shorter than it was before, for they fell from nine hundred, eight hundred, and seven hundred years to four hundred and three hundred, as we see in the age of Arphaxad, Salah, Heber: yea, they fell to two hundred and odd years, as we read of Peleg, Reu, Serug, and Tharah; yea, they came down to less than two hundred years. In the space of a few years man's life was again cut shorter by almost half, if not a full half. We read that Abraham lived but one hundred and seventy-five years, so that man's age ran very low then. See the account given in Scripture of Nahor, Sarah, Ishmael, Isaac, Jacob, Joseph (who died at a hundred) which confirms the same. And again the third time, man's life was shortened by almost another half, viz., about the year of the World 2,500, in Moses' time. For he sets the bounds of man's life thus: "The days of our years are threescore years and ten; and if by reason of strength they be fourscore years, yet is their strength labour and sorrow; for it is soon cut off, and we fly away." Ps 90:10. Eighty years is the utmost limit he sets man's life at, i.e., in the most ordinary and common account of man's life. Though some are of the opinion that these words do not give an account of the duration of man's life in general, but refer to the short lives of the Israelites in the wilderness, yet I do not see but it may take in both; and Moses who composed the Psalm, lived a hundred and twenty years himself, yet he might speak of the common term of man's life, and what usually happened to the generality of men. —John Edwards.