[INDOLOGY] source of upasarga grammar verse?

[Paul Hackett]

Dear colleagues,

   I am translating a late first millennium Indic Buddhist commentary in Tibetan translation that contains an unidentified quotation about the function of an upasarga.  I am hoping that someone might recognize the source.
   In glossing the meaning of _nye bar 'phrog_ (*upahriyante), the passage reads:

nye bar 'phrog cing zhes pa ni nye bar bsgyur ba dang bcas pa'i 'phrog pa'i skad kyi byings ni zhu ba'i don la 'jug ste

     nye bar gyur pa'i dbang gis ni,
     skad kyi byings las don gzhan 'gyur,
     gang gā'i chu ni mngar mod kyang,
     rgya mtsho'i chu yis ji bzhin no,

zhes bshad pas so,

which roughly translates as:

"The linguistic root, √hṛ (“to carry, surpass, destroy, remove”) together with the verbal prefix [upa-], conveys the meaning of ‘offering up’. Hence, [it is in accordance] with the explanation:

     Through the force of an upasarga, 
     [A verb] takes on a different meaning from its linguistic root, 
     Just as although the water of the Ganges is sweet, 
     [It is] likewise [transformed] by the water of the ocean."

If anyone recognizes this verse and knows its source, I would appreciate knowing it.

Thank you,

Paul Hackett
Columbia University