for aye

from The Collaborative International Dictionary of English v.0.48

Aye \Aye\, Ay \Ay\, adv. [Icel. ei, ey; akin to AS. [=a],
   [=a]wa, always, Goth. aiws an age, Icel. [ae]fi, OHG, ?wa, L.
   aevum, Gr. ? an age, ?, ?, ever, always, G. je, Skr. ?va
   course. ?, ?. Cf. {Age}, v., {Either}, a., {Or}, conj.]
   Always; ever; continually; for an indefinite time.
   [1913 Webster]

         For his mercies aye endure.              --Milton.
   [1913 Webster]

   {For aye}, {always}; forever; eternally.
      [1913 Webster]