Three worldly activities are considered essential for deciding our future life in the Hereafter, namely, keeping promises, restoring trust, and paying debt.
Any person who fails to fulfill any one of these three transactions eventually will lead himself to Hell in the Hereafter, therefore, we must keep our obligations to our fellow human beings as much as we keep our obligations to Allah (S.W.A). these two activities must fo hand in hand. We cannot fulfill one and ignore the other. Doing that makes our faith incomplete.