It's All Greek To Me Meaning

(idiomatic) I don’t understand any of it; it makes no sense.

Example: I tried reading the instructions, but it’s all Greek to me.
1599 — William Shakespeare, Julius Caesar, i 2
  but those that understood him smiled at one another and
shook their heads; but, for mine own part, it was Greek to me.
1694 — François Rabelais, Gargantua and Pantagruel, book V; translated by Pierre Motteux, 1694 (original French edition 1564)
  During the processions they trilled and quavered most melodiously betwixt their teeth I do not know what antiphones, or chantings, by turns. For my part, ’twas all Hebrew-Greek to me, the devil a word I could pick out on’t;
1844 — Frederick Marryat, The Settlers in Canada
  "Well," said Alfred, "it may be a letter, but I confess it is all Greek to me.
1849 — Herman Melville, Redburn. His First Voyage, ch VI
  I ran after him, and received an order to go aloft and “slush down the main-top mast.” This was all Greek to me, and after receiving the order, I stood staring about me, wondering what it was that was to be done.
1904 — George M. Fenn, The Ocean Cat’s Paw
  "Look here, Mr. Count," he said; "I am only a rough Englishman, and a lot of what you have been saying about mission and that sort of thing is just so much Greek to me."
1907 — H. G. Wells, The War in the Air
  "It’s more like some firm’s paper. All this printed stuff at the top. Drachenflieger. Drachenballons. Ballonstoffe. Kugelballons. Greek to me."
1927-1929 — Mahatma Gandhi, An Autobiography or The Story of my Experiments with Truth, Part II (VIII), translated 1940 by Mahadev Desai
  A Parsi lawyer was examining a witness and asking him question regarding credit and debit entries in account books. It was all Greek to me.
1965 — Harry Ray Bannister, The Education of a Broadcaster‎, page 16
  Cavanaugh explained the network-affiliate relationship, which of course was all Greek to me and remained so even after his explanation.
2004, Jacob Taubes, The Political Theology of Paul‎, page 99
  […] it was expected of me, or it was considered an honor, to lecture on seventeenth-century philosophy: Descartes (which was all Greek to me), Descartes to Spinoza.