TgO Gen15:6 :וְהֵימֵין בְמֵימְרָא דַיוי וְחַשבַה לֵיה לְזָכוּ‏ : he was loyal to the Lord's word and He reckoned it to his merit
See the entire entry for zāḵū, zāḵūṯā n.f. merit; victory

TgO Gen15:6 :וְחַשבַה לֵיה לְזָכוּ‏ : He considered it to be as a merit for him
See the entire entry for ḥšb vb. to think, calculate