8 In the same manner, we must remove from Christian Democracy another possible subject of reproach, namely, that while looking after the advantage of the working people it should seem to overlook the upper classes of society, for they also are of the greatest use in preserving and perfecting the commonwealth. The Christian law of charity, which has just been mentioned, will prevent us from so doing. For it embraces all men, irrespective of ranks, as members of one and the same family, children of the same most beneficent Father, redeemed by the same Saviour, and called to the same eternal heritage. Hence the doctrine of the Apostle, who warns us that "We are one body and one spirit called to the one hope in our vocation; one Lord, one faith and one baptism; one God and the Father of all who is above all, and through all, and in us all."(2) Wherefore, on account of the union established by nature between the common people and the other classes of society, and which Christian brotherhood makes still closer, whatever diligence we devote to assisting the people will certainly profit also the other classes, the more so since, as will be thereafter shown, their co-operation is proper and necessary for the success of this undertaking.
Source: Graves de Communi Re (Vatican.va)