In my recent edits I entirely removed the Abel quotes:
With the exception of the geometric series, there does not exist in all of mathematics a single infinite series whose sum has been determined rigorously...
The divergent series are the invention of the devil, and it is a shame to base on them any demonstration whatsoever. By using them, one may draw any conclusion he pleases and that is why these series have produced so many fallacies and so many paradoxes.
Though these quotes by Niels Henrik Abel have cropped up in a few quote sites (including for a time this one) as statements Euler, they are not actually widely attributed to him. ~ Kalki 22:46, 14 April 2006 (UTC)