Yelell
Mathers actually was highly instrumental in the Golden Dawn's reordering of the cards, which was based on the Hebrew Letter attributions of the Sepher Yetzirah.
So what he referenced of Mathers would be from before the reordering.
Here's the "sentence" Waite's talking for those who haven't seen it. It's from The Tarot—Its Occult Significance, Use in Fortune-Telling, and Method of Play, Etc. (Mathers, 1888). Mary linked to it above.
"Thus the whole series of the twenty-two trumps will give a connected sentence which is capable of being read thus:—The Human Will (1) enlightened by Science (2) and manifested by Action (3) should find its Realization (4) in deeds of Mercy and Beneficence (5). The Wise Disposition (6) of this will give him Victory (7) through Equilibrium (8) and Prudence (9), over the fluctuations of Fortune (10). Fortitude (11), sanctified by Sacrifice of Self (12), will triumph over Death itself (13), and thus a Wise Combination (14) will enable him to defy Fate (15). In each Misfortune (16) he will see the Star of Hope (17) shine through the twilight of Deception (18); and ultimate Happiness (19) will be the Result (20). Folly (0), on the other hand, will bring about an evil Reward (21)."