In that kingdom of blessedness the happy life will be made perfect in the Saints as it now is in the heavenly Angels; and therefore after the petition, “Thy kingdom come,” follows, “Thy will be done as in heaven, so in earth.” That is, as by the Angels who are in Heaven Thy will is done so as that they have fruition of Thee, no error clouding their knowledge, no pain marring their blessedness; so may it be done by Thy Saints who are on earth, and who, as to their bodies, are made of earth. So that, “Thy will be done,” is rightly understood as, ‘Thy commands be obeyed;’ “as in heaven, so in earth,” that is, as by Angels, so by men; not that they do what God would have them do, but they do because He would have them do it; that is, they do after His will.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Serm. in Mont., ii, 6