25 But, if Christian precepts prevail, the respective classes will not only be united in the bonds of friendship, but also in those of brotherly love. For they will understand and feel that all men are children of the same common Father, who is God; that all have alike the same last end, which is God Himself, who alone can make either men or angels absolutely and perfectly happy; that each and all are redeemed and made sons of God, by Jesus Christ, "the first-born among many brethren"; that the blessings of nature and the gifts of grace belong to the whole human race in common, and that from none except the unworthy is withheld the inheritance of the kingdom of Heaven. "If sons, heirs also; heirs indeed of God, and co-heirs with Christ."(22) Such is the scheme of duties and of rights which is shown forth to the world by the Gospel. Would it not seem that, were society penetrated with ideas like these, strife must quickly cease?
Source: Rerum Novarum (Vatican.va)