48 To be sure of eternal life, therefore, and to be able to help the poor effectively, it is imperative to return to a more moderate way of life, to renounce the joys, often sinful, which the world today holds out in such abundance; to forget self for love of the neighbor. There is a divine regenerating force in this "new precept" (as Christ called it) of Christian charity. Its faithful observance will pour into the heart an inner peace which the world knows not, and will finally cure the ills which oppress humanity.
Source: Divini Redemptoris (Vatican.va)