Primarily a reference to a 1789 quote by Benjamin Franklin:
Our new Constitution is now established, and has an appearance that promises permanency; but in this world nothing can be said to be certain, except death and taxes.
—Benjamin Franklin
First attested in 1726, but in common usage only as of the 19th century.
1907, F.B. Farmer, Brotherhood of Locomotive Firemen and Enginemen's Magazine[1], volume 43, A Dangerous Air Brake Practice, page 59:
This bad practice may be followed for years before the runaway follows, but that it will eventually is "as sure as death and taxes."
1908, The Insurance Age, volume 36, page 445:
"As sure as Death and Taxes", the old proverb says. But there's a difference. You may evade, dodge or lie out of your taxes, but Death will not be deceived or denied.
1824, Jonathan Swift, The novels of Swift, Bage and Cumberland, Hurst, Robinson, and Company, page 425:
Time, with his stealing steps, hath clawed me in his clutch, as the old song says: And this cursed gout; but it is what we must all come to. Nothing so sure as death and taxes.
1726, Daniel Defoe, chapter 6, in The History of the Devil, as well Ancient as Modern, second edition, The Modern History of the Devil, page 269:
Things as certain as Death and Taxes, can be more firmly believ'd: The Devil not have a Cloven-Foot!
