ـاد

Inherited from Middle Persian [script needed] (-ād, the third-person singular subjunctive ending).

ـاد • (-âd)

1. (obsolete, Classical Persian) may...; verbal suffix of the optative, attached to the present stem.
   • c. 1011, Abu'l-Qāsim Firdawsī, “The reign of Iskandar”, in شاهنامه [Book of Kings]‎^[1]:

     که یزدان ترا مزد نیکان دهاد
     بداندیش را درد پیکان دهاد

     ki yazdān tu-rā muzd-i nēkān dihād
     badandēš rā dard-i paykān dihād

     May God give the reward of the virtuous to you,
     May He give the torment of the spear to those of wicked thought.

     (Classical Persian romanization)

• In modern usage, it survives only in the word باد (bâd, “may... be”), the optative of بودن (budan, “to be”), in expressions such as زنده باد (zende bâd, “long live”).