Musar for Chagigah 26:10
ורבנן אמרי אותן שמכסות בהן רגליהם שנאמר (יחזקאל א, ז) ורגליהם רגל ישרה ואי לאו דאימעוט מנא הוה ידע דלמא דאיגלאי וחזיא ליה דאי לא תימא הכי ודמות פניהם פני אדם הכי נמי דאימעוט אלא דאיגלאי וחזיא ליה הכא נמי דאיגלאי וחזיא ליה
And the Rabbis say, "The ones that they would cover their legs with, as it is said, 'And their legs were one straight leg (Ezekiel 1:7),' and if the [wings covering the legs, as described in Isaiah 6:2] were not subtracted, how would he know? Maybe they were uncovered and he saw them. For if you don't say like this, [then regarding the verse], "And the likeness of their face [which was also covered by wings in Isaiah 6:2]: a man's face... (Ezekiel 1:10)," how [do you explain it]? Were they also subtracted? Rather, if they were uncovered and he saw them, here too, they [could have been] uncovered and he saw them.