The phrase "to repay the debt" means to return or give back something that was borrowed, lent or invested. It implies a sense of obligation and responsibility towards the person who provided the funds in the first place. The act of paying back the money with interest is seen as an expression of gratitude for being given the opportunity to use it. In essence, "to repay the debt" means to fulfill one's duty or commitment by making good on a promise made when obtaining credit or financial assistance.