Цитата красивая! Я попытался найти источник и, по всей видимости, не очень понятно действительно ли это сказал Ньютон:

“You may have seen this quote, attributed to Isaac Newton, but how sure is it that he actually said it? It does not appear in his writings. In fact, it seems it did not appear in print until a collection by Rev. Joseph Spence (1699-1768), Anecdotes, Observations and Characters, of Books and Men.1 There, it is purported to have been uttered by Newton “a little before he died” (1727), and was contributed by Andrew Michael Ramsey (1686-1743, known in France as Chevalier de Ramsay). However, note that the entry for Ramsay in the Dictionary of National Biography records he was in France at the time, only returning to England in 1730, which is after Newton's death. Thus it remains unclear how Ramsay came to know of the anecdote.“ [https://todayinsci.com/N/Newton_Isaac/NewtonIsaac-PlayingOnTheSeashore.htm]

В процессе поиска я набрёл на “список грехов”, который вёл Ньютон: https://www.newtonproject.ox.ac.uk/view/texts/normalized/ALCH00069
Это один из немногих сохранившихся личных документов Ньютона. Среди прочего он туда включил:
17. Stealing cherry cobs from Eduard Storer
18. Denying that I did so
ещё дважды “Relapse” и из интересного ещё “34. Not living according to my belief”
Ну, и немного для понимания религиозности Ньютона: “43. Missing chapel”