threescore years and ten the age of seventy as one's allotted span, with biblical allusion to Psalm 90:
You have set our iniquities before you,
our secret sins in the light of your presence.
All our days pass away under your wrath;
we finish our years with a moan.
Our days may come to seventy years,
or eighty, if our strength endures;
yet the best of them are but trouble and sorrow,
for they quickly pass, and we fly away.