PTPea 21.b:47[2] :אתה גמלת חסד למאן דמיתחמי ולא חמי דין דחמי ולא מתחמי יקבל פיוסך {ו}יגמול יתך חסד‏ : you showed kindness to one who is seen and does not see, may the One who sees and is not seen accept your plea and show you kindness
See the entire entry for gml vb. to repay